Joshua 5:4-6

This is why Joshua circumcised the men: After the Israelites left Egypt, all the men old enough to serve in the army died. They died in the desert on the way out of Egypt. The men who had come out of Egypt had been circumcised. But many were born in the desert on the trip from Egypt. They had not been circumcised. The Israelites had moved about in the desert for 40 years. During that time all the fighting men who had left Egypt had died. This was because they had not obeyed the Lord. So the Lord swore they would not see the land. This was the land he had promised their ancestors to give them. It was a land where much food grows.