TSK · Numbers 15:21

It is to belong to Aaron and to his sons from the Israelites, by a perpetual ordinance, for it is a contribution. It is to be a contribution from the Israelites from their peace offerings, their contribution to the LORD.

A priest of Aaron’s line will be with the Levites when the Levites collect the tithes, and the Levites will bring up a tenth of the tithes to the temple of our God, to the storerooms of the treasury.