NASB
"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."
— Joshua 5:6, NASB
“For the children of Israel walked forty years in the wilderness, till all the nation, even the men of war that came forth out of Egypt, were consumed, because they hearkened not unto the voice of Jehovah: unto whom Jehovah sware that he would not let them see the land which Jehovah sware unto their fathers that he would give us, a land flowing with milk and honey. ”
“Indeed, for forty years the Israelites traveled through the wilderness until all the men old enough to fight when they left Egypt, the ones who had disobeyed the LORD, died off. For the LORD had sworn a solemn oath to them that he would not let them see the land he had sworn by oath to their ancestors to give them, a land rich in milk and honey.”
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.
Now when they had finished circumcising all the nation, they remained in their places in the camp until they were healed.
Then the LORD said to Joshua, "Today I have rolled away the reproach of Egypt from you." So the name of that place is called Gilgal to this day.