Augustine of Hippo
Catena Aurea · Johannesevangelium 1
And John bare record, saying, I saw the Spirit descending from heaven like a dove, and it abode upon him. And I knew him not: but he that sent me to baptize with water, the same said unto me, Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Ghost. And I saw, and bare record that this is the Son of God.
(Aug. Tr. v. c. i) But who sent John? If we say the Father, we say true; if we say the Son, we say true. But it would be truer to say, the Father and the Son. How then knew he not Him, by Whom he was sent? For if he knew not Him, by Whom he wished to be baptized, it was rash in him to say, I have need to be baptized by Thee. So then he knew Him; and why saith he, I knew Him not?