“He shall drink of the torrent on the way; therefore shall he lift up his head” (Ps 109:7). Let us consider what it means that he drinks from the torrent on the way. First of all, what is the torrent? It is the flow of human mortality (profluxio mortalitatis humanae). Just as a torrent arises from the waters of the rain and overflows and roars and rushes and runs down and ends its course, so it is with the whole course of mortality. People are born, they live, they die. When some die, others are born, and when these die, still others succeed to them: they come, they go, and they too will not remain. What can be held on to? What is there that does not run off? What is there that, gathered from the rain, does not go on into the abyss? Just as a river suddenly rising from the rain, from drops of rain, goes into the sea and is seen no more, just as it was not seen before the rains made it rise, so this human race arises in secret and flows on and with death it is once again secret. Between the two it roars and passes.
It is from this torrent that Christ drank; he did not disdain to drink from it. For him to drink from this torrent was to be born and to die. This torrent is birth and death. Christ accepted this. He was born and he died: that is how he drank from the torrent on the way. For “he exulted like a giant to run the way” (Ps 18:6). He drank from the torrent on his way, for “he did not stay in the way of sinners” (Ps 1:1). And because he drank from the torrent on his way, for that reason “he lifted up his head.” For it was because he “lowered himself and was made subject to death, to death on the cross that God lifted him from the dead and gave him the name that is above every other name, so that at the name of Jesus every knee should bend of things in heaven, on earth, and under the earth, and every tongue should confess that Jesus Christ is Lord, in the glory of God the Father (Phil 2: 8-11). (EnPs 109, 20; PL 37, 1462)
Earlier in the same homily, Augustine had spoken of the “torrent of time”: “Now, in the midst of your enemies, now in this passage of ages, in this propagation and succession of human mortality, now while the torrent of time (torrens temporum) slips by, the sceptre of your power is directed so that you may rule in the midst of your enemies.” (#11; PL 37, 1454)