Numbers 32:13

32:13 So the Lord’s anger was kindled against the Israelites, and he made them wander in the wilderness for forty years, until all that generation that had done wickedly before the Lord was finished.

Numbers 35:6

35:6 Now from these towns that you will give to the Levites you must select six towns of refuge to which a person who has killed someone may flee. And you must give them forty-two other towns.