Numbers 18:26-28

Duties of Priests and Levites

²⁶ "Moreover, you shall speak and say to the Levites, 'When you take from the people of Israel the tithe that I have given you from them for your inheritance, then you shall present a contribution from it to the Lord, _g a tithe of the tithe. ²⁷ _h And your contribution shall be counted to you as though it were the grain of the threshing floor, and as the fullness of the winepress. ²⁸ So you shall also present a contribution to the Lord from all your tithes, which you receive from the people of Israel. And from it you shall give the Lord's contribution to Aaron the priest.

1. Cross References
   Nehemiah 10:38
   And the priest, the son of Aaron, shall be with the Levites when the Levites receive the tithes. And the Levites shall bring up the tithe of the tithes to the house of our God, to the chambers of the storehouse.
   
2. Cross References
   Numbers 18:30
   Therefore you shall say to them, 'When you have offered from it the best of it, then the rest shall be counted to the Levites as produce of the threshing floor, and as produce of the winepress.