Numbers 18:26-28 King James Version (KJV)
26 Thus 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.
27 And this your heave offering shall be reckoned unto you, as though it were the corn of the threshingfloor, and as the fulness of the winepress.
28 Thus 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.
Nehemiah 10:37-38 King James Version (KJV)
37 And that we should bring the firstfruits of our dough, and our offerings, and the fruit of all manner of trees, of wine and of oil, unto the priests, to the chambers of the house of our God; and the tithes of our ground unto the Levites, that the same Levites might have the tithes in all the cities of our tillage.
38 And the priest the son of Aaron shall be with the Levites, when the Levites take tithes: and the Levites shall bring up the tithe of the tithes unto the house of our God, to the chambers, into the treasure house.