When Jesus desires baptism, he does it as the sole good one, the one without sin, the one who does not need forgiveness, different from all human beings. As the good one, he desires baptism, even though he does not need it for himself, for the sake of those who need it, for the sake of sinners.  Precisely because he is the sole good one, he doesn’t allow himself to be separated from sinners; he does not become a Pharisee who wants to claim what is good for himself. The sinlessness, the goodness of Jesus, is attested precisely in his unconditional love for sinners. Jesus goes to baptism not out of penitence but out of love and in this way takes the side of sinners.

Dietrich Bonhoeffer, Meditation on Epiphany, January 1940

What sort of baptism is this, when the one who is dipped is purer than the font, and where the water that soaks the one whom it has received is not dirtied but honored with blessings? What sort of baptism is this of the Savior, I ask, in which the streams are made pure more than they purify? For by a new kind of consecration the water does not so much wash Christ as submit to being washed.

St. Maximus of Turin, Sermon 13A