Joshua 5:3-7 NASB1995
So Joshua made himself flint knives and circumcised the sons of Israel at Gibeath-haaraloth. This is the reason why Joshua circumcised them: all the people who came out of Egypt who were males, all the men of war, died in the wilderness along 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 along the way as they came out of Egypt had not been circumcised. For the sons of Israel walked forty years in the wilderness, until all the nation, that is, the men of war who came out of Egypt, perished because they did not listen to the voice of the LORD, to whom the LORD had sworn that He would not let them see the land which the LORD had sworn to their fathers to give us, a land flowing with milk and honey. Their children whom He raised up in their place, Joshua circumcised; for they were uncircumcised, because they had not circumcised them along the way.
NASB1995: New American Standard Bible - NASB 1995