Tractates on the Gospel of John

⁴ Behold, then, we have now heard the Gospel, where He answered the Jews who were indignant “that He not only broke the Sabbath, but said also that God was His Father, making Himself equal with God.” For so it is written in the foregoing paragraph. When, therefore, the Son of God, the Truth, made answer to their erring indignation, says He, “Verily, verily, I say unto you, The Son cannot of Himself do anything, but what He sees the Father doing;” as if He said, “Why are you offended because I have said that God is my Father, and that I make myself equal with God?

I am equal in that wise that He begot me; I am equal in that wise that He is not from me, but I from Him.” For this is implied in these words: “The Son cannot do anything of Himself, but what He sees the Father doing.” That is, whatever the Son has to do, the doing it He has of the Father. Why of the Father has He the doing it? Because of the Father He has it that He is Son. Why has He it of the Father to be Son? Because of the Father He has it that He is able, of the Father that He is.

For, to the Son, both to be able and to be is the self-same thing. It is not so with man. Raise your hearts by all means from a comparison of human weakness, that lies far beneath; and should any of us perhaps reach to the secret, and, while awe-struck by the brilliance as it were of a great light, should discern somewhat, and not remain wholly ignorant; yet let him not imagine that he understands the whole, lest he should become proud, and lose what knowledge he has gotten.

With man, to be and to be able are different things. For sometimes the man is, and yet cannot what he wills; sometimes, again, the man is in such wise, that he can what he wills; therefore his being and his being able are different things. For if man's esse and posse were the same thing, then he could when he would. But with God it is not so, that His substance to be is one thing, and His power to be able another thing; but whatever is His, and whatever He is, is consubstantial with Him, because He is God: it is not so that in one way He is, in another way is able; He has the esse and the posse together, because He has to will and to do together.

Since, then, the power of the Son is of the Father, therefore also the substance of the Son is of the Father; and since the substance of the Son is of the Father, therefore the power of the Son is of the Father. In the Son, power and substance are not different: the power is the self-same that the substance is; the substance to be, the power to be able. Accordingly, because the Son is of the Father, He said, “The Son cannot of Himself do anything.” Because He is not Son from Himself, therefore He is not able from Himself.