Octave Day of the Epiphany
The Gospel tells us that John saw the Holy Ghost come down upon Jesus, and that he gave "testimony that he was the Son of God" who "appeared on earth in the substance of our flesh" (Collect).
Deus, cujus Unigénitus in substántia nostrae carnis appáruit: praesta, quaesumus; ut per eum, quem símilem nobis foris agnóvimus, intus reformári mereámur.
O God, whose only begotten Son appeared in the substance of our flesh, grant, we beseech Thee, that we may be inwardly reformed by Him, whom we recognize to have been outwardly like unto ourselves.
Continuation of the Holy Gospel according to John
The next day, John saw Jesus coming to him, and he saith: Behold the Lamb of God, behold him who taketh away the sin of the world. This is he, of whom I said: After me there cometh a man, who is preferred before me: because he was before me. And I knew him not, but that he may be made manifest in Israel, therefore am I come baptizing with water. And John gave testimony, saying: I saw the Spirit coming down, as a dove from heaven, and he remained upon him. And I knew him not; but he who sent me to baptize with water, said to me: He upon whom thou shalt see the Spirit descending, and remaining upon him, he it is that baptizeth with the Holy Ghost. And I saw, and I gave testimony, that this is the Son of God.
(St John 1:29-34)