Joshua 5:1-5

And it came to pass, when all the kings of the Amorites, that were beyond the Jordan westward, and all the kings of the Canaanites, that were by the sea, heard how that Jehovah had dried up the waters of the 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. At that time Jehovah said unto Joshua, Make thee knives of flint, and circumcise again the children of Israel the second time. And Joshua made him knives of flint, and circumcised the children of Israel at the hill of the foreskins. And this is the cause why Joshua did circumcise: all the people that came forth out of Egypt, that were males, even all the men of war, died in the wilderness by the way, after they came forth out of Egypt. For all the people that came out were circumcised; but all the people that were born in the wilderness by the way as they came forth out of Egypt, they had not circumcised.