Joshua 5:1-5

Now when all the Amorite kings west of the Jordan and all the Canaanite kings along the coast heard how the LORD had dried up the Jordan before the Israelites until they had crossed over, their hearts melted in fear and they no longer had the courage to face the Israelites. At that time the LORD said to Joshua, “Make flint knives and circumcise the Israelites again.” So Joshua made flint knives and circumcised the Israelites at Gibeath Haaraloth. Now this is why he did so: All those who came out of Egypt—all the men of military age—died in the wilderness on the way after leaving Egypt. All the people that came out had been circumcised, but all the people born in the wilderness during the journey from Egypt had not.