They are wholly given unto him. The word nethunim (wholly given) is emphatic here, and in Numbers 8:16. As the whole house of Israel at large, so especially (for a reason which will presently appear) the tribe of Levi belonged absolutely to God; and he, as absolutely, made them over to Aaron and the priests for the service of his sanctuary.
Cf. Ephesians 4:11, "gave some apostles," etc. The Levites, as gifts from God (nethunim) to their brethren the priests, must be distinguished from the nethinim or serfs of foreign extraction given by the congregation to the Levites to do their most menial work for them (Joshua 9:27).