Q. 10. What are the personal properties of the three persons in the Godhead?
A. It is proper to the Father to beget the Son (Heb. 1:5-6, 8), and to the Son to be begotten of the Father (John 1:14, 18), and to the Holy Ghost to proceed from the Father and the Son from all eternity (John 15:26; Gal. 4:6).
Regarding the personal relation of the Holy Spirit to the Father and the Son, there was a controversy between the western churches and the eastern churches. Does the Holy Spirit proceed from the Father alone, or does he also proceed from the Son? The East held to the former, the West to the latter. This question was debated for centuries in the Middle Ages which culminated in one of the causes of the Great Schism between the East and West (1054). The West added to the Nicene Creed the words “and the Son” (filioque) to the line, “The Holy Ghost…who proceeds from the Father and the Son.” The Eastern Orthodox church objected to the unilateral way this was added to the Creed, and because they disagree with the theology of it.  Petrus Van Mastricht (1630-1706) concludes about this controversy:
“There was sin here on both sides: by the Latins because they added something to the Constantinopolitan Creed, and in so doing intended obliquely to extend the authority of the pope to the Greeks; but by the Greeks because they rashly rejected a dogma consistent with the Scriptures and acknowledged by the more ancient Fathers of the church, out of mere ill-will toward the name of the Latins.” 
Francis Turretin (1623-1687) adds, “Although the Greeks ought not to have been charged with heresy on account of their opinion, nor ought it to have been the occasion of a schism arising or continuing, still the opinion of the Latins may be properly retained as more agreeable to the words of Scripture and the truer… If in certain primitive creeds the expression filioque was omitted (proving the procession from the Son), this was because at that time there had been no controversy agitated concerning the procession of the Holy Spirit. Yet it was prudently added afterwards on account of rising errors.” 
Statement of the Question
Turretin clarifies specifically what this question entails and what it does not entail:
“The question does not concern the temporal and external procession (which is terminated on creatures by which the Holy Spirit is sent to sanctify us and make perfect the work of salvation); but the question concerns the eternal and internal procession (which is terminated inwardly and is nothing else than the mode of communication of the divine essence, i.e., that by which the third person of the Trinity has from the Father and the Son the same numerical essence which the Father and the Son have).” 
Wilhelmus à Brakel (1635-1711) explains how Scripture reveals the eternal procession of the Spirit, just as it reveals the eternal begottenness of the Son, and that the Father is unbegotten:
“The Son proceeds from the Father by way of eternal generation, and the Holy Spirit proceeds from the Father and the Son in a manner which can best be described by “to breathe.” (1) The word “spirit” as it occurs in Hebrew and Greek conveys this idea. (2) For this reason He is called the “breath of the Almighty” (Job 33:4), and “the breath of His mouth” (Ps 33:6). (3) This manner of operation is congruent with His manner of existence. The third Person works by way of breathing, and it is also the manner of His existence. “The wind bloweth where it listeth…so is every one that is born of the Spirit” (John 3:8). For this reason Jesus also availed Himself of such symbolism when He promised the Spirit to His disciples. “He breathed on them, and saith unto them, Receive ye the Holy Ghost” (John 20:22). In like manner also the apostles were filled with the Holy Spirit, an event which was accompanied with the sound of a rushing mighty wind (Acts 2:2).” 
The Filioque Proven From Scripture
1. The Spirit of Christ
Scripture describes the Holy Ghost not only as the Spirit of the Father (Mat. 10:20), but also the Spirit of the Son and the Spirit of Christ. “God hath sent forth the Spirit of His Son into your hearts” (Gal 4:6); “Now if any man have not the Spirit of Christ, he is none of His” (Rom 8:9); “searching what, or what manner of time the Spirit of Christ which was in them did signify” (1 Pet 1:11). “For I know that this shall turn to my salvation through your prayer, and the supply of the Spirit of Jesus Christ…” (Phil 1:19). If the Spirit proceeds solely from the Father, and not also from the Son, then none of these verses can be cogently explained. Further, Mastricht adds, “He is called the Spirit of the mouth of the Lord Jesus (2 Thess. 2:8), in the same way as in Psalm 33:6 he is called the Spirit of the mouth of the Father.”  The Father sends the Spirit in the name of Christ, “But the Comforter, which is the Holy Ghost, whom the Father will send in my name…” (John 14:26). These texts describe the eternal, unchangeable, and ineffable relationship between the Son and the Spirit.
2. The Son sends the Holy Ghost
Scripture also reveals to us that God the Son sends the Holy Spirit. “The Comforter…whom I will send unto you from the Father” (John 15:26); “But if I depart, I will send Him unto you” (John 16:7). “And when he had said this, he breathed on them, and saith unto them, Receive ye the Holy Ghost:” (John 20:22). “Turn you at my reproof: behold, I will pour out my spirit unto you, I will make known my words unto you.” (Prov. 1:23). “And, behold, I send the promise of my Father upon you: but tarry ye in the city of Jerusalem, until ye be endued with power from on high.” (Luke 24:49).
While some may interpret these texts as being exclusively about the temporal and outward economic (ad extra) activity of the Holy Spirit (such as his outpouring at Pentecost, Acts 2), it cannot be separated from the Spirit’s eternal mode of subsistence (ad intra). As Brakel writes, “What is true for His manner of operation is also true for His manner of existence. The manner of His operation is a necessary consequence of His manner of existence.”  This is because “the being or essence of a thing is the foundation or principium of its activity or operation, and all things operate in a manner proper or proportionate to what they are.”  Antonius Thysius (1565-1640) likewise makes this plain, “For even the sending of the Holy Spirit within time, although it is not the same as the eternal procession, nevertheless has its groundings in the origin and order of persons. For this reason the Father is sent by no-one, because He is from no-one except himself; the Son is sent by the Father, because He is from the Father. And in the same way the Holy Spirit is sent by both of them, because He is from both of them.” 
Mastricht, perhaps controversially, adds another proof to this class of texts: “The river of the water of life, bright as crystal (by which nothing more fitting is understood than the Holy Spirit; cf. Isa. 44:3; John 7:38; Ezek. 36:25-26) is said to proceed from the throne of God and of the Lamb (Rev. 22:1).” 
3. The Spirit imparts what He receives from the Son
Thirdly, the single procession of the Spirit from both Father and Son  is confirmed in such texts in which it is stated that the Holy Spirit imparts to the elect that which he receives from the Son, just as the Son speaks what he has received from the Father (John 14:10). “Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. He shall glorify me: for he shall receive of mine, and shall shew it unto you. All things that the Father hath are mine: therefore said I, that he shall take of mine, and shall shew it unto you.” (John 16:13-15). As William Perkins (1558-1602) explains:
“Christ says, ‘The Holy Ghost hath received of mine which he shall show unto you‘ (John 16:14)—namely, knowledge and truth to be revealed unto His church. Where we may reason thus: the [divine] person receiving knowledge from another receives essence also. The Holy Ghost receives truth and knowledge from Christ to be revealed unto the church. And therefore, first of all, He has received substance and essence from the Son.” 
4. The Difference Between the Son and the Spirit
If the Spirit proceeds only from the Father, how is this different than the relation of the Son to the Father? Mastricht answers, “If his procession from the Son is denied, then the order of subsisting and of operating in the Trinity will be disturbed in no small measure: if the Holy Spirit immediately proceeds from the Father just like the Son does, there will hardly be anything, besides generation and spiration, by which the procession of the Son and the Holy Spirit might be sufficiently distinguished from each other.” 
5. The Trinitarian Order
Rejecting the procession of the Spirit from the Son also would necessarily disturb the order of persons in the trinity. As Thysius wrote, “Thus also the personal order among the divine persons would be destroyed, and the Holy Spirit would no longer be the third person, but He would be positioned in an order and ranking equal to the Son, and, as it were, placed over against Him.” 
6. The Unity of the Son and the Spirit
Thysius continues, “And lastly, because the relation and relatedness demands this [personal order among the divine persons], for otherwise there would be no relatedness at all between the Son and the Holy Spirit. And this would be contrary to the definition in Holy Scriptures.”  Herman Bavinck (1854-1921) similarly writes that, in the Eastern Orthodox scheme, the Son and Spirit “are more or less independent of each other: they both open their own way to the Father.” 
‘From‘ the Son or ‘through‘ the Son?
What is the difference between the Spirit being sent from the Father and through the Son (per filium) vs. being sent from the Father and the Son (filioque)? This formulation is consistent with some in the early church, and was used at the Council of Florence (1439) in an attempt to reconcile the schism, but “the orientals who subscribed to this receded from the transaction and still vehemently persist in their former opinion.”  Some have pointed out that it is semantics and essentially a distinction without a difference. Edward Leigh (1602-1671) does not excuse the East from error for denying the source of the Spirit’s procession to the Son, but grants that this formulation is less egregious:
“To deny the procession of the Holy Ghost from the Son, is a grievous error in Divinity, and would have grated the foundation, if the Greek Church had so denied the procession of the Holy Ghost from the Son, as that they had made an inequality between the Persons. But since their form of speech is, ‘That the Holy Ghost proceedeth from the Father by the Son, and is the Spirit of the Son,‘ without making any difference in the consubstantiality of the Persons, it is a true, though an erroneous Church in this particular. Diverse learned men think, that a filio & per filium in the sense of the Greek Church, was but a question in modo loquendi in manner of speech, and not fundamental.” 
Mastricht concurred, “There are many who think that both the ancient and especially the more recent Greeks intend nothing other than that the Holy Spirit proceeds from the Father alone, through the Son. Thus their opinion would be more tolerable, since the Father works all things through the Son, and in this way the controversy would almost fade into a mere contest over words.”  Wilhelmus à Brakel clarifies the biblical and Reformed position and explains the acceptable and unacceptable ways this phrasing can be used:
“The operations of both the Father and the Son relative to the procession of the Holy Spirit should not be viewed as proceeding from two distinctly different origins, for it is one and the same operation and power. Both the Father and the Son ought rather to be viewed as the primary cause of all that transpires, rather than viewing the Son as a primary cause of lesser importance, implying that the Father would cause the Holy Spirit to proceed by means of the Son. If, however, we consider manner and order of both existence and operation, then the Holy Spirit proceeds from the Father and from the Son, as well as from the Father through the Son.” 
Similarly, Turretin distinguishes between the origin and principle of the procession and the order and mode of the procession:
“Since breathing virtue is numerically one in the Father and the Son, it is not good to say that in this respect the Spirit proceeds from the Father through the Son (as if he was principally from the Father, but secondarily and less principally from the Son). If the mode of subsisting is considered (according to which the Father is the fountain of deity from whom the Son emanates), not improperly in this sense is he said to proceed from the Father through the Son (as to the order and mode of procession).” 
So according to Brakel and Turretin, it is not appropriate to posit that the Spirit proceeds from the Father (as the origin and principle) and through the Son (as a means of the Spirits origin), but it is acceptable to say that the order and mode of the Spirit’s procession is from the Father and through the Son while still affirming his procession from both. In short, the Holy Spirit proceeds from both the Father and the Son equally, but in a different way from each. Yet, if one uses the phrase to reject that the Spirit proceeds from the Son, then it is a serious error. Thysius, having just argued strongly for the filioque, explains the Eastern formulation more sympathetically. While affirming that the Spirit, as to the origin of procession, “comes from both” Father and Son, emphasizes that, with regard to the manner of procession, He proceeds in a mediate way:
“But in order to put the controversy between the Greeks and Latins in its proper place and settle it, some have conveniently said, in keeping with the phraseology of some ancient authors, that the Father spirates the Holy Spirit through the Son, and that the Holy Spirit proceeds from the Father through the Son. For by that manner of speaking it is shown that He comes from both; and the mode of subsistence is shown, too; that is to say, He proceeds in a mediate and subordinate way from the Father through the Son. Thereby the Greeks’ position is not destroyed, namely that the one and even personal principle of the spiration and procession of the Holy Spirit is the Father—because the Father precedes in origin and order. To be precise: their position of the personal starting point is the Father on account of the Father’s antecedence in origin and rank. And hereby both the relationship and subordination of the Spirit to the Son is established (John 15:16 and 16:14-15).” 
Thysius then beautifully illustrates how this interpersonal relation works in reverse:
“Moreover, by reason of the origin, the mode of relation, and the order which the Holy Spirit has towards the Father and Son, the following property arises: Just as the Holy Spirit has everything from the Father and the Son (or from the Father through the Son) and therefore acts and operates in a similar way, so too does He render everything to the Father through the Son. And in this regard there is a certain eminence and worthiness from the Father himself and the Son towards the Holy Spirit, which is entirely a matter of origin and order alone.” 
How Generation and Spiration differ: Satisfaction in mystery vs. extra-biblical speculation
How do the eternal generation of the Son, and the eternal procession of the Spirit differ? While this question is easier to answer for us than for the East, it is not without difficulty and mystery. Francis Turretin explains, “That this procession differs from the generation of the Son cannot be denied because they are different persons who stand related to each other in origin. But the nature of this distinction cannot be explained and may more safely be unknown than inquired into. Hence John of Damascus says ‘that there is a difference between generation and procession, we have learned, but what the nature of the distinction is we by no means understand.’ And Augustine: ‘There is a difference between generation and procession, but I know not how to distinguish them because both are inexpressible.'” 
George Sohnius (1551-1589), “As to how the Son’s generation differs from the procession of the Holy Spirit, i.e., what the property is and, as it were, the formal distinction between generation and procession, on account of which the second person only is and is called the Son and the third only the Spirit, the doctors of the early Church, Augustine and the Damascene and other admit their ignorance, since it has not been expressly defined in God’s Word.” Jacob Alting (1618-1679): “Έκπόρευσις [procession] is distinguished from generation, but how, we don’t know.” 
But the relative silence of Scripture on this question did not always stop Western Christians from attempting to answer it without Scripture. Johann Heidegger (1633-1698) recounts, “Venturing to turn aside from the restraint of the ancients and the path of Scripture, the Scholastics so defined the difference between generation and procession that they assigned the former to intellect (intellectus), the latter to will (voluntas) and love (charitas).” And while some Reformed theologians made critical use of this analogy, the vast majority rejected it.  Heidegger continues, “This is plainly άλογον [irrational and unbiblical]. Since Father, Son, and Holy Spirit have intellect and will equally, it would follow that the Son is generated by His own intellect, the Spirit breathed by His own will.”  Likewise Gisbertus Voetius (1589-1676), “criticized these formulations as speculative, identifying them as learned ignorance (docta ignorantia) or a speculative question (quaestio curiosa). According to Voetius, the Word does not proceed as divine cognition or as generation through the intellect; the Spirit is not produced per modum amoris [by way of love] and amor [love] is not the proper name of the Holy Spirit.” 
Bernardinus De Moor (1709-1780) notes that this Medieval vain philosophy and “hallucination” has been a cause of stumbling to Muslims and an occasion for entrenchment in their rejection of the Trinity (and, one could add, a confirming of their error of doing theology without the infallible Scriptures):
“In this way they entangle the matter further, since Generation and Spiration are personal Operations; but to understand and to will are rather essential acts. Whence Ahmed the Persian, a Mohammedan by profession, from this Scholastic explanation of Generation and Procession, acutely, and not unhappily, impugns the mystery of the Trinity, by arguing in this way: Knowledge and Love in God, the former an act of the intellect, as it were, the latter of the will, are essential; therefore, not the foundation of a personal relation.” 
Turretin similarly concludes that such doctrinal innovation “is unsupported by Scripture, so it entangles rather than explains the thing.” He continues, “They speak more wisely who, stammering in a matter so difficult, place the distinction in three things:”
(1) In the principle: because the Son emanates from the Father alone, but the Holy Spirit from the Father and the Son together. [Muller elaborates, “Thus the Father is the principium of the Son, whereas the Father and the Son together are the principium of the Spirit.” (PRRD vol. 4, p. 377)]
(2) In the mode: because the Son emanates by way of generation, which terminates not only on the personality, but also on the similarity (on account of which the Son is called the image of the Father and according to which the Son receives the property of communicating to another person the same essence; but the Spirit by way of spiration, which terminates only on the personality and by which the proceeding person does not receive the property of communicating that essence to another person).
(3) In the order: because as the Son is the second person and the Spirit the third, generation, in our mode of conceiving, precedes spiration (although they are really coeternal).” 
Thomas Ridgeley (1667-1734) concludes, “Some divines have used similitudes to explain the doctrine of the Trinity. These, at best, tend only to illustrate, and not to prove a doctrine. We can hardly make use of them for illustrating the doctrine of the Trinity without conveying some ideas which are unbecoming of it, if not subversive of it; and while we pretend to explain that which is in itself inexplicable, we do no service to the truth… I would, therefore, conclude this head, by using the words of God to Job, ‘Who is this that darkeneth counsel by words without knowledge?‘ (Job 38:2) Who are these that, by pretending to illustrate the doctrine of the Trinity by similitudes, do that, which, though very foreign to their design, tends to pervert it?” 
OBJ. 1. “Double procession” makes the Son the same as the Father.
Richard Muller summarizes this objection and response, “The Greek critique of the filioque, that it implied two ultimate principia or archai in the Godhead, did not hold—for there could only be two archai if the Father and the Son separately and equally were the sources of the Spirit’s procession. The orthodox conception of the filioque, however, insisted on the unity of the act of the Father and the Son, so that the Holy Spirit proceeds from Father and Son by “one and the same breathing” and does so from both equally, the Father and the Son acting in communion with one another. Thus, the Holy Ghost, the third person, proceeds from the Father and the Son: ‘and albeit the Father and the Son are distinct persons, yet they are both but one beginning of the holy Ghost.‘” 
OBJ. 2. From John 15:26.
Deniers of the filioque emphasize that John 15:26 only says that the Spirit proceeds from the Father. “…the Spirit of truth, which proceedeth from the Father…” Mastricht responds, “(a) That passage, because of the lack of an exclusive, does not extend in meaning further than to say that the Holy Spirit proceeds from Father, which is not disputed. (b) If they do not intend anything other than that the Holy Spirit proceeds from the Father alone, but through the Son, then it does not supply me much that I would oppose. Meanwhile, (c) the passage seems to speak not so much about his hypostatic procession as about his economic procession, which occurs in time.”  See also the Reformed exegesis of this passage above.
OBJ. 3. Inconsistency in Western Trinitarian doctrine.
Mastricht addresses this objection, “If they should allege that as a result of the opinion of the Latins the order of the persons in the Trinity is disturbed in no small measure, and that perhaps it is more correctly said that the Holy Spirit proceeds from the Father through the Son, the same way the particles ἐκ, διά, and εἰς seem to be employed in Romans 11:36, just as Basil, Theophylact, John of Damascus, and others have said, as witnessed by Cardinal Basilios Bessarion in the Council of Florence, I respond: (a) I do not object greatly, although (b) the passage in Romans 11:36 does not seem to be occupied with the procession of the Holy Spirit, and much less to speak about his hypostatic procession, but only about the production of creatures by God, and the conservation of them through providence, and the direction of the same to his glorification. But (c) notwithstanding, the order of subsisting will obtain accurately enough if it is stated that the Holy Spirit proceeds from the Father and from the Son, when the Father is said simply not to proceed from any, the Son to proceed from the Father by eternal generation, and the Holy Spirit to proceed from both by one procession or active spiration.” 
OBJ. 4. No explicit statements in Scripture.
William Perkins writes, “But some peradventure will say, where is it written in all the Bible in express words that the Holy Ghost proceeds from the Son as He proceeds from the Father? Answer. The Scripture says not so much in plain terms, yet we must know that that which is gathered from thence by just consequence is no less the truth of God than that which is expressed in words. Hereupon all churches save those in Greece with one consent acknowledge the truth of this point.” 
 “The Orthodox objected (and still object) to this addition to the Creed, for two reasons. First, the Creed is the common possession of the whole Church, and if any change is to be made in it, this can only be done by an Ecumenical Council. The west, in altering the Creed without consulting the east, is guilty (as Khomiakov put it) of moral fratricide, of a sin against the unity of the Church. In the second place, most Orthodox believe the Filioque to be theologically untrue. They hold that the Spirit proceeds from the Father alone, and consider it a heresy to say that He proceeds from the Son as well. There are, however, some Orthodox who consider that the Filioque is not in itself heretical, and is indeed admissible as a theological opinion – not a dogma – provided that it is properly explained. But even those who take this more moderate view still regard it as an unauthorized addition.” (Timothy Ware, The Orthodox Church, p. 51).
 Petrus Van Mastricht, Theoretical-Practical Theology, vol. 2, p. 583.
 Francis Turretin, Institutes of Elenctic Theology III.xxxi, vol. 1, pp. 308 & 310.
 Turretin, IET III.xxxi.2, vol. 1, p. 308.
 Wilhelmus à Brakel, The Christian’s Reasonable Service, pp. 172-3.
 Mastricht, ibid., p. 583.
 Brakel, ibid., p. 173.
 Richard Muller, Dictionary of Latin and Greek Theological Terms, modus operandi, p. 221.
 Synopsis of a Purer Theology IX.xviii, (Brill), vol. 1, p. 237.
 Mastricht, ibid., p. 583.
 I have not used the phrase “double procession” because it tends to imply two origins of the Spirit, or a plurality of processions. This terminology is consistent with the eastern side’s strawman of the biblical position (cf. Objection 1).
 William Perkins, Exposition of the Apostles’ Creed, Works V, p. 308. Likewise Mastricht, “Christ in John 16:14-15 says of the Holy Spirit, ‘He will receive of what is mine,‘ just as he says of himself, ‘All things that the Father has are mine.‘ But he did not receive in time what he would declare, so then he received it from eternity—and how from eternity unless by procession?” And Turretin, “Whatever the Spirit has, he has from the Son no less than from the Father (Jn. 16:13–15), and as the Son is said to be from the Father because he does not speak of himself, but of the Father (from whom he receives all things), so the Spirit ought to be said to be and to proceed from the Son because he hears and speaks from him.”
 Mastricht, ibid., p. 583.”spiratio: spiration or procession; the personal property of the Spirit and his personal relation (relatio personalis) to the Father and the Son, strictly defined as the inward act by which the Father and the Son simultaneously and eternally produce the Spirit from their own substance, without division of substance, and entirely within the one divine essence. The scholastics also distinguish between spiratio activa, which is the activity of the Father and the Son spirating, and spiratio passiva, which is the movement of the Spirit being spirated.” (Richard Muller, Dictionary of Latin and Greek Theological Terms, ed. 2 (2017), p. 341).
 Synopsis IX.xvi, vol. 1, p. 237.
 Synopsis IX.xvi, vol. 1, p. 237.
 Herman Bavinck, Reformed Dogmatics, vol. 2, p. 317.
 Francis Turretin, Institutes of Elenctic Theology III.xxxi.4, vol. 1, p. 308. The first decree of the Eastern Orthodox Synod of Jerusalem (1672), in response to the confession of Cyril Lukaris (1629), expressly rejects Lukaris’ use of “the Holy Spirit proceeding from the Father through the Son.“
 Edward Leigh, Body of Divinity II.xvi, p. 214.
 Mastricht, ibid., p. 583.
 Brakel, ibid., pp. 173-4.
 Turretin, IET III.xxxi.8, vol. 1, p. 310.
 Synopsis IX.xix, vol. 1, p. 237-9. The Oxford Handbook of Early Modern Theology notes the “remarkable openness of some Reformed to the Eastern Orthodox position on the filioque clause. While maintaining the Western position that the Spirit proceeds from both the Father and the Son, the Leiden Synopsis and Cocceius showed clear sympathy for the Eastern argumentation and tried to mediate between the Western and Eastern concerns.” (p. 205).
 Synopsis IX.xx, vol. 1, p. 239.
 Francis Turretin, Institutes of Elenctic Theology III.xxxi.3 (John Damascene, Exposition of the Orthodox Faith 1.8 (NPNF2, 9:9; PG 94.824); Augustine, Contra Maximinum 2.14, PL 42.770). Some secondary sources attribute this quote to Leonard Rijssen (1636-1700), but Rijssen compiled a “Compendium of the Didactic and Elenctic Theology of Francis Turretin,” where it is difficult to tell which words are Rijssen’s own, and which are Turretin’s. While Heppe attributes this to Rijssen, I was able to find it in Turretin. Rijssen scholar Wes White, writes that this work “can best be described as Turretin’s Institutes abridged into a Rijssen framework…it is not often clear which words are Rijssen’s and which words are Turretin’s. However, a simple guide is that most of the brief statements are from Rijssen, and most of the longer statements are from Turretin. The consequence is that around ninety percent of the work consists of quotations from Turretin. There has been much confusion in the secondary literature on this point. Most of them seem to be unaware of the shorter work.” (A Translation with Introduction to A Summary of Elenctic Theology by Leonard Rijssen, pp. l-li, 2009).
Benedict Pictet similarly wrote: “That procession may be distinguished from generation can be demonstrated from the fact that the Holy Spirit is always said to proceed from, and never to have been begotten by, the Father; nor is he ever called the image of God—but we must not curiously inquire into the nature of the difference. Let us guard against the unbridled and unsuccessful boldness of the schoolmen, who attempt to explain it: I certainly do not grasp the distinction between generation and procession, I am not desirous of this, nor am I able.” (Benedict Pictet, Christian Theology II.xx.4; cited from Richard Muller, Post Reformation Reformed Dogmatics vol. 4, p. 376).
 George Sohnius, Opera Tom. I, p. 89; Jacob Alting, Methodus Theolgiae Didacticae, 18. Cited from Heinrich Heppe, Reformed Dogmatics, p. 130.
 e.g. William Ames (Marrow of Theology V.16) and Keckermann (System of Theology I.iii, pp. 28-33). “The usual unwillingness of the Protestant scholastics to enter into a lengthy discussion of the way in which the emanations of the second and third persons of the Trinity differ represents a rather significant example of the difference between medieval and Protestant scholasticism: the Protestants revert to the caveat of Gregory of Nazianzen against excessive inquiry into the mystery and emulate the Reformers in their somewhat reserved acceptance of the tradition without further explanation. The extensive and frequently cogent speculation of the medieval doctors concerning the relation of the emanations to the divine nature, intellect, and will (itself an extension of the Augustinian metaphors) is simply ignored by most of the Reformed orthodox.” (Richard Muller PRRD, IV p. 376). Muller further notes that the Reformed Orthodox “relative gentleness of the criticism derives, perhaps, from [their] recognition that some of their Reformed predecessors had adopted the medieval solutions on this point.” (ibid., p. 377).
 Medulla Theologiae Christianae IV.41; cited from Heinrich Heppe, Reformed Dogmatics, p. 130.
 “See Syllabus problematum, ii, iv (fol. 11, 12).” (Editor, Synopsis of a Purer Theology, (Brill), vol. 1, p. 235). Thysius similarly concludes: “But because Holy Scripture does not make this claim so transparently and distinctly, we judge that an honest admission of ignorance is to be preferred to an all too daring assertion. And we prefer to await eagerly that day when we shall see God face to face, and when we shall know perfectly and fully what we know only in part here.” (Synopsis 8.17, vol 1, p. 213-5). “For us it suffices that somehow by means of these different words and concepts the difference is indicated in the production of the divine persons; and we do not presume to give definitions recklessly to matters that cannot be expressed in words.” (Synopsis 9.14, vol. 1, p. 235).
 Bernardinus De Moor, Didactico-Elenctic Theology V:12.
 Turretin, IET III.xxxi.3.
 Thomas Ridgeley, Body of Divinity, vol. 1, p. 147.
 Muller, PRRD vol. 4, p. 375.
 Mastricht, ibid., p. 584.
 Mastricht, ibid., p. 584.
 Perkins, ibid., p. 308. cf. George Gillespie on good and necessary consequences deduced from Scripture, A Treatise of Miscellany Questions, ch. 20.