11 Again the Lord spoke to Moses , saying , 12 "Now, behold , I have taken the Levites from among the sons of Israel instead of every firstborn , the first issue of the womb among the sons of Israel . So the Levites shall be Mine. 13 "For all the firstborn are Mine; on the day that I struck down all the firstborn in the land of Egypt , I sanctified to Myself all the firstborn in Israel , from man to beast . They shall be Mine; I am the Lord ."

Matthew Henry's Commentary on Numbers 3:11-13

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.