Chapter 8.--No Addition Can Be Made to the Nature of God.
Since, therefore, the Father alone, or the Son alone, or the Holy Spirit alone, is as great as is the Father and the Son and the Holy Spirit together, [616] in no manner is He to be called threefold. Forasmuch as bodies increase by union of themselves. For although he who cleaves to his wife is one body; yet it is a greater body than if it were that of the husband alone, or of the wife alone. But in spiritual things, when the less adheres to the greater, as the creature to the Creator, the former becomes greater than it was, not the latter. [617] For in those things which are not great by bulk, to be greater is to be better. And the spirit of any creature becomes better, when it cleaves to the Creator, than if it did not so cleave; and therefore also greater because better. "He," then, "that is joined unto the Lord is one spirit:" [618] but yet the Lord does not therefore become greater, although he who is joined to the Lord does so. In God Himself, therefore when the equal Son, or the Holy Spirit equal to the Father and the Son, is joined to the equal Father, God does not become greater than each of them severally; because that perfectness cannot increase. But whether it be the Father, or the Son, or the Holy Spirit, He is perfect, and God the Father the Son and the Holy Spirit is perfect; and therefore He is a Trinity rather than triple.
[616] [Each trinitarian person is as great as the Trinity, if reference be had to the essence, but not if reference be had to the persons. Each person has the entire essence, and the Trinity has the entire essence. But each person has the essence with only one personal characteristic; while the Trinity has the essence with all three personal characteristics. No trinitarian person is as comprehensive as the triune Godhead, because he does not possess the two personal characteristics belonging to the other two persons. The Father is God, but he is not God the Son and God the Holy Spirit.--W.G.T.S.]
[617] [The addition of finite numbers, however great, to an infinite number, does not increase the infinite. Similarly, any addition of finite being to the Infinite Being is no increase. God plus the universe is no larger an infinite than God minus the universe. The creation of the universe adds nothing to the infinite being and attributes of God. To add contingent being to necessary being, does not make the latter any more necessary. To add imperfect being to perfect being, does not make the latter more perfect. To add finite knowledge to infinite knowledge, does not produce a greater amount of knowledge. This truth has been overlooked by Hamilton, Mansell, and others, in the argument against the personality of the Infinite, in which the Infinite is confounded with the All, and which assumes that the All is greater than the Infinite--in other words, that God plus the universe is greater than God minus the universe.--W.G.T.S.]
[618] 1 Cor. vi. 17
Chapter 9.--Whether One or the Three Persons Together are Called the Only God.
10. And since we are showing how we can say the Father alone, because there is no Father in the Godhead except Himself, we must consider also the opinion which holds that the only true God is not the Father alone, but the Father and the Son and the Holy Spirit. For if any one should ask whether the Father alone is God, how can it be replied that He is not, unless perhaps we were to say that the Father indeed is God, but that He is not God alone, but that the Father, Son, and Holy Spirit are God alone? But then what shall we do with that testimony of the Lord? For He was speaking to the Father, and had named the Father as Him to whom He was speaking, when He says, "And this is life eternal, that they may know Thee the one true God." [619] And this the Arians indeed usually take, as if the Son were not true God. Passing them by, however, we must see whether, when it is said to the Father, "That they may know Thee the one true God," we are forced to understand it as if He wished to intimate that the Father alone is the true God; lest we should not understand any to be God, except the three together, the Father, Son, and Holy Spirit. Are we therefore, from the testimony of the Lord, both to call the Father the one true God, and the Son the one true God, and the Holy Spirit the one true God, and the Father, the Son, and the Holy Spirit together, that is, the Trinity itself together, not three true Gods but one true God? Or because He added, "And Jesus Christ whom Thou hast sent," are we to supply "the one true God;" so that the order of the words is this, "That they may know Thee, and Jesus Christ whom Thou hast sent, the one true God?" Why then did He omit to mention the Holy Spirit? Is it because it follows, that whenever we name One who cleaves to One by a harmony so great that through this harmony both are one, this harmony itself must be understood, although it is not mentioned? For in that place, too, the apostle seems as it were to pass over the Holy Spirit; and yet there, too, He is understood, where he says, "All are yours, and ye are Christ's, and Christ is God's." [620] And again, "The head of the woman is the man, the head of the man is Christ, and the head of Christ is God." [621] But again, if God is only all three together, how can God be the head of Christ, that is, the Trinity the head of Christ, since Christ is in the Trinity in order that it may be the Trinity? Is that which is the Father with the Son, the head of that which is the Son alone? For the Father with the Son is God, but the Son alone is Christ: especially since it is the Word already made flesh that speaks; and according to this His humiliation also, the Father is greater than He, as He says, "for my Father is greater than I;" [622] so that the very being of God, which is one to Him with the Father, is itself the head of the man who is mediator, which He is alone. [623] For if we rightly call the mind the chief thing of man, that is, as it were the head of the human substance, although the man himself together with the mind is man; why is not the Word with the Father, which together is God, much more suitably and much more the head of Christ, although Christ as man cannot be understood except with the Word which was made flesh? But this, as we have already said, we shall consider somewhat more carefully hereafter. At present the equality and one and the same substance of the Trinity has been demonstrated as briefly as possible, that in whatever way that other question be determined, the more rigorous discussion of which we have deferred, nothing may hinder us from confessing the absolute equality of the Father, Son, and Holy Spirit.
[619] John xvii. 3
[620] 1 Cor. iii. 22, 23
[621] 1 Cor. xi. 3
[622] John xiv. 28
[623] 1 Tim. ii. 5