Joshua 5:4-6

This is the reason Joshua circumcised them: all the people who came out of Egypt, who were males, even 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 children of Israel walked forty years in the wilderness until all the nation, even the men of war who came out of Egypt, were consumed, because they didn’t listen to the LORD’s voice. The LORD swore to them that he wouldn’t let them see the land which the LORD swore to their fathers that he would give us, a land flowing with milk and honey.