Numbers 18:22-25

²²that the sons of Israel nigh no more to the tabernacle of the bond of peace, neither do deadly sin.

²³To the sons alone of Levi, serving me in the tabernacle, and bearing the people’s sins, it shall be a lawful thing everlasting in your generations.

²⁴They shall wield none other thing, and they shall be satisfied with the offering of tithes, which I separated into the uses and necessaries of them.

²⁵And the Lord spake to Moses and said,