Joshua 5:3

It happened, when all the kings of the Amorites, who were beyond the Jordan westward, and all the kings of the Canaanites, who were by the sea, heard how that Yahweh had dried up the waters of the Jordan from before the children of Israel, until we had passed over, that their heart melted, neither was there spirit in them any more, because of the children of Israel.

At that time, Yahweh said to Joshua, "Make flint knives, and circumcise again the children of Israel the second time.

This is the reason Joshua circumcised: all the people who came out of Egypt, who were males, even all the men of war, died in the wilderness by the way, after they came out of Egypt.

For all the people who came out were circumcised; but all the people who were born in the wilderness by the way as they came out of Egypt had not been circumcised.