Joshua 5:1
And it came to pass, when all the kings of the Amorites, which were on the side of Jordan westward, and all the kings of the Canaanites, which were by the sea, heard that the LORD had dried up the waters of Jordan from before the children of Israel, until we were passed over, that their heart melted, neither was there spirit in them any more, because of the children of Israel.
The Amorite kings west of the Jordan and the Canaanite kings by the sea heard that the Lord had dried up the waters of the Jordan from before the children of Israel until they had passed over. At the time the Jordan was swollen, fast-flowing and impetuous, which made the passage over on dry land a greater miracle. When the kings heard, their hearts melted with fear and terror, leaving them without courage or spirit because of the children of Israel.
God held back the waters in order to increase the fear with which the surrounding nations regarded Israel and so prepare the way for Israel's easier and complete triumph in Canaan. This terror added to the fear already caused because Israel had slain the five kings of Midian, Sihon king of the Amorites, and Og of Bashan. Their terror also followed and was increased by Israel's slaying and defeat of two kings, described in some accounts as two Moabite kings. The crossing gave unmistakable evidence to the Canaanites, to all Israel, and to Joshua himself that the living God, the King of heaven and earth, was among His people and that He would not fail them nor forsake them.
The fear ended the enemies' confidence, taunt, and claim that Israel's God could not bring His people into Canaan. The crossing ended the reproach of Egypt, for the heathen had reproached the Lord and His people because Israel had not yet possessed Canaan but had wandered long in the wilderness, proudly claiming God was not able to lead them in. Now that Israel had passed over the Jordan on dry land, the enemies could no longer reproach them.