Deuteronomy 2:7, 14

The LORD your God has blessed you in all the work of your hands. He has watched over your journey through this vast wilderness. These forty years the LORD your God has been with you, and you have not lacked anything.

Thirty-eight years passed from the time we left Kadesh Barnea until we crossed the Zered Valley. By then, that entire generation of fighting men had perished from the camp, as the LORD had sworn to them.