Chapter 3

As Israel crosses the Jordan, the Ark of the Covenant is carried before them, by the Levites.  The people are to stay back 2000 cubits, to be sure they go the right way.  The Lord also speaks to Joshua, and instructs him.  It would seem that at this time, God is communicating directly to Joshua, as He had with Moses.  These verses:

7 The LORD said to Joshua, "Today I will begin to exalt you in the sight of all Israel, that they may know that, as I was with Moses, so I will be with you. 8 And as for you, command the priests who bear the ark of the covenant, 'When you come to the brink of the waters of the Jordan, you shall stand still in the Jordan.'" [Jos 3:7-8 ESV]

God lets Joshua know that He is about to promote him in the eyes of the people.  It won't just be that Moses said so, nor will it be that they have said so, but God is going to make it clear to all that He has chosen Joshua to lead, and that as He was with Moses, so he will be with Joshua.

Joshua says as the priests enter the water of the Jordan, the water from upstream will pile up, and they will cross on dry land.  The water is stopped well upstream, as the river is in flood this time of year.  The city where it piled up is called Adam.  Hard to resist the pun there.  A dam.  Where the water was piled up.