The Number and Duties of the Levites

31 And these 'are' births of Aaron and Moses, in the day of Jehovah's speaking with Moses in mount Sinai. 2 And these 'are' the names of the sons of Aaron: the first-born Nadab, and Abihu, Eleazar, and Ithamar; 3 these 'are' the names of the sons of Aaron, the anointed priests, whose hand he hath consecrated for acting as priest. 4 And Nadab dieth—Abihu also—before Jehovah, in their bringing near strange fire before Jehovah, in the wilderness of Sinai, and sons they had not; and Eleazar—Ithamar also—acteth as priest in the presence of Aaron their father. 5 And Jehovah speaketh unto Moses, saying, 6 'Bring near the tribe of Levi, and thou hast caused it to stand before Aaron the priest, and they have served him, 7 and kept his charge, and the charge of all the company before the tent of meeting, to do the service of the tabernacle; 8 and they have kept all the vessels of the tent of meeting, and the charge of the sons of Israel, to do the service of the tabernacle; 9 and thou hast given the Levites to Aaron and to his sons; they are surely given to him out of the sons of Israel. 10 'And Aaron and his sons thou dost appoint, and they have kept their priesthood, and the stranger who cometh near is put to death.' 11 And Jehovah speaketh unto Moses, saying, 12 'And I, lo, I have taken the Levites from the midst of the sons of Israel instead of every first-born opening a womb among the sons of Israel, and the Levites have been Mine; 13 for Mine 'is' every first-born, in the day of My smiting every first-born in the land of Egypt I have sanctified to Myself every first-born in Israel, from man unto beast; Mine they are; I 'am' Jehovah.'

Matthew Henry's Commentary on Numbers 3:1-13

Commentary on Numbers 3:1-13

(Read Numbers 3:1-13)

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.