Augustine of Hippo, on Ps 71:8

“And he shall rule from sea to sea, and from the river unto the ends of the earth.”

“Where? At the river Jordan. That, you see, is where Christ's work of teaching began. It was there that the baptism of Christ that was to come was commended to us, because the previous kind of baptism was received there, and the one preparing the way, and saying, "Prepare a way for the Lord, make straight his paths." The Lord, you see, wished to be baptized by the servant, so that those who are baptized by the Lord might appreciate what it is they receive. So he began from the very place where prophecy had very properly preceded him: "He will have dominion from sea to sea, and from the river to the limits of the whole wide world." At the very river where Christ began to have dominion, John saw Christ, recognized him, bore witness to him.”

Imported from an open dataset — not yet checked against the printed edition.