| Gill's Exposition of the Entire Bible And thou shalt give the Levites unto Aaron and to his sons,.... To be their ministers and servants: they are wholly given unto him out of the children of Israel: even all of them entirely, none excepted; the whole tribe which were not in the priestly office; those were separated from the rest of the tribes of Israel, and appointed for the service of the priests: or they were "given, given" (q); which is repeated not only to show that they were wholly given, as we render it, but to denote the certainty of it, that they were really given; and especially to declare the freeness of the gift; the priests had them as free gifts, nor did they pay them any thing for, their service; they were maintained another way, namely, by the tithes of the people; and indeed the priests received a tithe out of the tithe of the Levites; so far were they from contributing any thing to their support, or in consideration of the service they did them. (q) "dati, dati", Pagninus, Montanus, Vatablus, Drusius.
Keil and Delitzsch Biblical Commentary on the Old TestamentMoses was also to give the Levites to Aaron and his sons. "They are wholly given to him out of the children of Israel:" the repetition of נתוּנם here and in Numbers 8:16 is emphatic, and expressive of complete surrender (Ewald, 313). The Levites, however, as nethunim, must be distinguished from the nethinim of non-Israelitish descent, who were given to the Levites at a later period as temple slaves, to perform the lowest duties connected with the sanctuary (see at Joshua 9:27).
Geneva Study BibleAnd thou shalt give the Levites unto Aaron and to his {f} sons: they are wholly given unto him out of the children of Israel. (f) Aaron's sons the priests served in the sanctuary in praying for the people and offering sacrifice: the Levites served for the inferior uses of the same.
Wesley's Notes 3:9 Given to him - To attend upon him and observe his orders, and ease him of his burden.
Jamieson-Fausset-Brown Bible Commentary9. they are wholly given unto him out of the children of Israel, &c.-The priests hold the place of God, and the Levites are the servants of God in the obedience they render to the priests.
Matthew Henry's Concise Commentary3:1-13 There was much work belonging to the priests' office, and there were now only Aaron and his two sons to do it; God appoints the Levites to attend them. Those whom God finds work for, he will find help for. The Levites were taken instead of the first-born. When He that made us, saves us, as the first-born of Israel were saved, we are laid under further obligations to serve him faithfully. God's right to us by redemption, confirms the right he has to us by creation. | 
