You 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.

And it shall be a perpetual statute of the children of Israel to Aaron and his sons, for this is a separate offering; and it shall be a special offering from the children of Israel, from the peace offerings of the children of Israel, a special offering to the Lord.