Hebrews 7:5
And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham:
Cross-reference
Hebrews 7:10 reveals that Levi, through Abraham, also paid tithes to Melchizedek, deepening the argument about priesthood superiority over the Levitical tithe system.
Leviticus 27:30-33 details the tithe law on produce and herds, foundational to the Levitical tithe system invoked in Hebrews 7:5.
Numbers 18:21-26 is the direct law giving Levites all tithes, which Hebrews 7:5 summarizes as the commandment.
2 Chronicles 31:4-6 records faithful tithing under Hezekiah, illustrating the law that Hebrews 7:5 refers to.
Numbers 18:26-32 adds that Levites must tithe their own tithe to priests—a related but distinct regulation from the command in Hebrews 7:5.
Nehemiah 13:10 shows the result of neglecting tithe payments—Levites left their service—contrasting with the command in Hebrews 7:5.