18:26Thus speak unto the Levites, and say unto them, When ye take of the children of Israel the tithes which I have given you from them for your inheritance, then ye shall offer up an heave offering of it for the LORD, even a tenth part of the tithe.

18:28Thus ye also shall offer an heave offering unto the LORD of all your tithes, which ye receive of the children of Israel; and ye shall give thereof the LORD'S heave offering to Aaron the priest.