Joshua 5:3-6

³And Joshua made himself sharp knives, and circumcised the children of Israel at the hill of 'Araloth.

⁴And this is the cause why Joshua did circumcise: All the people that came out of Egypt, the males, all the men of war, died in the wilderness on the way, after their going forth out of Egypt.

⁵For all the people that came out were circumcised; but all the people that were born in the wilderness on the way at their going forth out of Egypt, they had not circumcised.

⁶For during forty years the children of Israel wandered in the wilderness, till there was an end of all the people, the men of war, who were come out of Egypt, who had not obeyed the voice of the Lord; unto whom the Lord had sworn that he would not let them see the land, which the Lord had sworn unto their fathers that he would give unto us, a land flowing with milk and honey.