How was the Jordan crossing different for the Canaanites from the earlier Red Sea miracle?
The Canaanites had only heard reports of the Red Sea miracle from 40 years earlier, but the Jordan crossing happened near them, likely witnessed firsthand as the river dammed up by invisible power, causing their hearts to melt in fear.
Les explains that the kings of the Amorites west of the Jordan had heard how God dried up the waters of Jordan from before the children of Israel until they passed over, and their hearts melted. They had earlier heard about the Red Sea deliverance from Egypt, as Rahab rehearsed 40 years later. But now they were close enough, probably eyewitnesses, of seeing the old Jordan River suddenly dammed up by an invisible power. That immediate proof that Israel's God was still alive and miraculous produced the fear of God in them.