Numbers 18:9, 19

This shall be yours of the most holy things, [reserved] from the fire: every offering of the people, every grain offering and sin offering and guilt offering, which they shall render (give) to Me, shall be most holy for you and for your sons.

All the offerings of the holy things, which the Israelites offer to the LORD I have given to you and to your sons and your daughters with you as a continual allotment. It is an everlasting covenant of salt [that cannot be dissolved or violated] before the LORD to you and to your descendants with you.”