Rashi's Deed Analogy and Everlasting Covenant

Chapter 18 details the responsibilities and duties as well as the gifts and privileges of the Kohanim (priests) and the Leviim (Levites). We talk about 24 different "gifts" that must be given to the priests/Levites.

In many cases, they are God's representatives, and the only way to fulfill our obligations to God is in fact to offer various items - foodstuffs or livestock - to the priest.