Hebrews 7:5 - Matthew Poole's English Annotations on the Holy Bible

This is a proof by instance out of the Levitical law, that he who receiveth is greater than he who giveth. And verily they that are of the sons of Levi, who receive the office of the priesthood: the seed of Levi the son of Jacob, son of Isaac, son of Abraham, Numbers 1:48-50 3:1-5, and not all of them neither, but the sons of Levi descending from Aaron, were separated and consecrated in the priesthood by God's precept, and vindicated from those who would usurp it, Numbers 16:1-17:13, and confirmed in it by miracle. Have a commandment to take tithes of the people according to the law: God himself gave them a law from heaven to tithe by, and a charge to observe this law, as to all parts of tithes, such as were due to all Levites, Numbers 18:24, to the high priest only as God's substitute, Numbers 18:8-19,25-29; to the Levites, widows, and poor together, Deuteronomy 14:22-29. These the same law obliged all the Israelites to pay to these Levites as a homage due from them to God, and so delivered to his substitutes superior unto them, as his priests and ministers, and due to them by his own constitution, being the first-fruits of his own blessing. That is, of their brethren, though they come out of the loins of Abraham: yet these Israelites who were to pay those tithes to these as superior to them in office, were their own brethren by nature, of the same rank, coming out of the same loins of Abraham, but subjected to these priests, who, by God's ordinance, were set above them in their office; and their receiving tithes was an inseparable property of that superiority.