Numbers 18:26-29

²⁶You shall also speak to the Levites, and shall say to them, If you° take the tithe from the children of Israel, which I have given you from them for an inheritance, then shall you° separate from it a heave-offering to the Lord, a tenth of the tenth.

²⁷And your heave-offerings shall be reckoned to you as corn from the floor, and an offering from the wine-press.

²⁸So shall you° also separate them from all the offerings of the Lord out of all your tithes, whatever you° shall receive from the children of Israel; and you° shall give of them an offering to the Lord to Aaron the priest.

²⁹Of all your gifts you° shall offer an offering to the Lord, and of every first-fruit the consecrated part from it.