Augustine of Hippo
Catena Aurea · Johannesevangelium 7
Now about the midst of the feast Jesus went up into the temple, and taught. And the Jews marvelled, saying, How knoweth this man letters, having never learned? Jesus answered them, and said, My doctrine is not mine, but his that sent me. If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself. He that speaketh of himself seeketh his own glory: but he that seeketh his glory that sent him, the same is true, and no unrighteousness is in him.
(Tract. xxix. s. 3) Mine is not mine, appears a contradiction; why did He not say, This doctrine is not Mine? Because the doctrine of the Father being the Word of the Father, and Christ Himself being that Word, Christ Himself is the doctrine of the Father. And therefore He calls the doctrine both His own, and the Father’s. A word must be a word of some one’s. What is so much Thine as Thou, and what is so much not Thine as Thou, if what Thou art, Thou art of another. His saying then, My doctrine is not Mine own, seems briefly to express the truth, that He is not from Himself; it refutes the Sabellian heresy, which dares to assert that the Son is the same as the Father, there being only two names for one thing.