It happened, when the priests who bore the ark of the covenant of Yahweh were come up out of the midst of the Jordan, and the soles of the priests' feet were lifted up to the dry ground, that the waters of the Jordan returned to their place, and went over all its banks, as before.
It is a good custom to memorialize God’s great acts for us so that we will remember them and so that our children will learn that God is powerful and faithful. Baptism is one such memorial for the Christian, and the Lord’s Supper is another.