Hebrews 7:5

If Melchisedec was greater than Abraham, he was greater than Abraham's descendants, including the tribe of Levi.

They that are of the sons of Levi who receive, etc. [ο ι ε κ τ ω ν υ ι ω ν λ ε υ ε ι λ α μ β α ν ο ν τ ε ς]. Those out of the sons of Levi who become priests. Not those who receive the priesthood from the sons of Levi. Not all Levites were priests, but only those of the house of Aaron.

The office of the priesthood [τ η ν ι ε ρ α τ ι α ν]. Only here and Luke 1:9. A commandment [ε ν τ ο λ η ν]. A special injunction, See on James 2:8; Ephesians 2:15.

To take tithes [α π ο δ ε κ α τ ο ι ν]. See on ver. 4.

That is of their brethren, though they come out of the loins of Abraham. The people, the brethren of the Levites, are descended from their common ancestor, Abraham, yet the Levites exact tithes from them.