Origen here shows that the early Church saw the sacrament of baptism not only as the crossing of the Red Sea, but also as the crossing of the Jordan River into the promised land.
The ark of the covenant led the people of God across the Jordan. The priests and the Levites halted, and the waters, as though out of reverence to the ministers of God, stopped flowing. They piled up in a single mass, thus allowing the people of God to cross in safety.
As a Christian, you should not be amazed to hear of these wonders performed for men of the past. The divine Word promises much greater and more lofty things to you who have passed through Jordan’s stream by the sacrament of baptism: he promises you a passage even through the sky. Listen to what Paul says concerning the just: We shall be caught up in the clouds to meet Christ in heaven, and so we shall always be with the Lord.
There is absolutely nothing for the just man to fear; the whole of creation serves him. Listen to another promise that God makes him through the prophet: If you pass through fire, the flame shall not burn you, for I am the Lord your God. The just man is everywhere welcome, and everything renders him due service.
So you must not think that these events belong only to the past, and that you who now hear the account of them do not experience anything of the kind. It is in you that they all find their spiritual fulfilment. You have recently abandoned the darkness of idolatry, and you now desire to come and hear the divine law. This is your departure from Egypt. When you became a catechumen and began to obey the laws of the Church, you passed through the Red Sea; now at the various stops in the desert, you give time every day to hear the law of God and to see the face of Moses unveiled by the glory of God.
But once you come to the baptismal font and, in the presence of the priests and deacons, are initiated into those sacred and august mysteries which only those know who should, then, through the ministry of the priests, you will cross the Jordan and enter the promised land. There Moses will hand you over to Jesus, and He himself will be your guide on your new journey.
Mindful, then, of all the mighty works of God, remembering that he divided the sea for you and held back the waters of the river, you will turn to them and say: Why was it, sea, that you fled? Jordan, why did you turn back? Mountains, why did you skip like rams, and you hills, like young sheep? And the word of the Lord will reply: The earth is shaken at the face of the Lord, at the face of the God of Jacob, who turns stones into a pool and rock into springs of water.
This post on baptism as crossing the Jordan into the Promised Land is used in the Roman Catholic Office of Readings for Wed of the Tenth week of the year. It is an excerpt from a homily on Joshua (Hom 4, 1: PG 12, 842-843) by Origen, an early church father who died in 252AD.