Numbers 18:26-28

CAB(i) 26 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. 27 And your heave offerings shall be reckoned to you as grain from the threshing floor, and an offering from the winepress. 28 So shall you also separate them from all the offerings of the Lord out of all your tithes, whatsoever you shall receive from the children of Israel; and you shall give to them of the Lord's offering, to Aaron the priest.