10 But hear a far stronger, a far more expressive testimony. See ye what it is we are treating of; see ye that to love any person in place of Christ is adultery. Why do I say this? Let us attend to the voice of John. People could be mistaken in him, could think him to be the person he was not. He rejects the false honor, in order to hold the truth complete. See what he declares Christ to be; what does he say himself is? “He that has the bride is the bridegroom.” Be chaste, love the bridegroom.
But what are you, who sayest to us, “He that has the bride is the bridegroom? But the friend of the bridegroom, who stands and hears him, rejoices greatly because of the bridegroom's voice.” The Lord our God will help me in proportion to the tumult of my heart, for it is full of sadness, to utter the grief I feel; but I beseech you by Christ Himself to imagine in thought what it will not be possible for me to utter; for I know that my grief cannot be expressed with befitting impressiveness.
Now I see many adulterers who desire to get possession of the bride, purchased at so great a price, loved while deformed that she might be made fair, having been purchased and delivered and adorned by such an one; and those adulterers strive with their words to be loved instead of the bridegroom. Of that One it is said, “This is He that baptizes.” Who is he that goes forth from us and says, “I am he that baptizes”? Who is he that goes forth from us and says, “That is holy which I give”? Who is he that goes hence and says, “It is good for you to be born of me”? Let us hear the friend of the bridegroom, not the adulterers against the bridegroom; let us hear one jealous, but not for himself.
Source: Tractates on the Gospel of John (New Advent)