And the LORD said to Aaron, "You shall have no inheritance in their land, neither shall you have any portion among them. I am your portion and your inheritance among the people of Israel.”
God made it clear to Aaron and his descendents that the priestly duties of service to Him were a unique blessing and privilege. God blesses Aaron and his family with this birthright. Other Israelites might get land and houses in the Promised Land. The priests and Levites would get God Himself as their inheritance.
This chapter contains details for the support of the priests and of worship of Yahweh. All the tithes and offerings that came in would be collected by the priests. From that, 90% was available to support the priestly class. The top 10% was offered by the priests as their tithe (a tithe of the tithes) before the Lord. The rest was used to provide for all the priests and Levites and their families who guarded and served in the worship of the Lord. When God told Aaron He would be his portion, He backed it up with real support from the nation of Israel. God would provide for His servants. He would use His people to do this.
It interests me how much those involved in such ministry would need to trust God. They were forbidden from having any other means of support. When times were hard, they had to see God provide quite literally through His people. And the bulk of the budget for operating the sacrificial system was labor. 90% of the received gifts went to provide for priests, Levites, and their families. A lot of people were dependent upon God being their portion and inheritance!