Numbers 18:24

18:24 But I have given to the Levites for an inheritance the tithes of the Israelites that are offered to the Lord as a raised offering. That is why I said to them that among the Israelites they are to have no inheritance.”

Numbers 18:28

18:28 Thus you are to offer up a raised offering to the Lord of all your tithes which you receive from the Israelites; and you must give the Lord’s raised offering from it to Aaron the priest.