Psalms 114:3

But, again, listen to another excellent steward of God, whom I reverence as a father, for in Christ Jesus he begat me through the gospel, and from this servant of Christ I received the laver of regeneration. I speak of the blessed Ambrose, whose grace, constancy, labors, dangers, whether in works or in speech, for the catholic faith, I myself have experienced, and together with me the Roman world does not hesitate to proclaim them. When this man was explaining the Gospel according to Luke, he said, "The Jordan turned backwards" signified the future mysteries of the laver of salvation, through which infants who are baptized at the beginning of their natural life are reformed from badness.

Nor ought it to appear at all improbable that at the command of God the bones were fitted again to their joints, since we have numberless instances in which nature has obeyed the commands of heaven; as the earth was commanded to produce the green herb3 and did produce it; as the rock at the touch of the rod produced water for the thirsting people; and the hard stone poured forth streams by the mercy of God for those parched with heat. What else did the rod changed into a serpent5 signify than that at the will of God living things can be produced from those that are without life? Do you think it more incredible that bones should come together when commanded than that streams should be turned back or the sea flee? For thus does the prophet testify: "The sea saw it and fled; Jordan was driven back." Nor can there be any doubt about this fact, which was proved by the rescue of one and the destruction of the other of two peoples, that the waves of the sea stood restrained and at the same time surrounded one people and poured back on the other for their death, that they might overwhelm the one but preserve the other. And what do we find in the Gospel itself? Did not the Lord himself prove there that the sea grew calm at a word, the clouds were driven away, the blasts of the winds yielded, and that on the quieted shores the dumb elements obeyed God?

The water was cleansed, which was enriched with the warmth of the Lord's blessing, although it was common and cold. Consequently, what previously had scarcely washed away worldly stains on objects now purifies the spiritual stains on souls. And do not marvel at the fact that we say that water, that is, a bodily substance comes to have the power to purify a soul. It clearly comes to have that power; it penetrates all the recesses of the conscience. For although water itself is delicate and fine, nonetheless by Christ's blessing it was made even more delicate and entered through the hidden conditions of life into the secret places of the soul with its spiritual dew. For the course of blessings is more delicate than the pathways of water. Thus we also say that the blessing in our Savior's baptism, which flowed down like a spiritual river, dyed the courses of all eddies and the water-courses of all fonts. When Christ entered the Jordan, the rivers of waters streamed in a marvelous manner, but the floods of blessings also ran. From the one side the eddy of the riverbed was carried along more boisterously; from the other side the most pure font of the Savior was trickling down; and in some bewildering manner the consecration of baptism was going upstream to the source of the Jordan, and the river of blessings was being borne contrary to the direction the waters were flowing. This is why (or so I think) holy David said, "The Jordan turned back." For in the baptism of Christ the Jordan did not turn back in its own waters but in the sacraments, and it traced its source in the blessing of its nature rather than in its substance. For while the grace of consecration is spread abroad on all fonts through him, it seems that its own course has gone back to the origin of its channels.