Cross reference
Numbers 18:26
26 Moreover thou shalt speak unto the Levites, and say unto them, When ye take of the children of Israel the tithe which I have given you from them for your inheritance, then ye shall offer up a heave-offering of it for Jehovah, a tithe of the tithe.
Nehemiah 10:38
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.
Numbers 18:21
21 And unto the children of Levi, behold, I have given all the tithe in Israel for an inheritance, in return for their service which they serve, even the service of the tent of meeting.