11 God spoke to Moses: 12 "I have taken the Levites from among the People of Israel as a stand-in for every Israelite mother's firstborn son. The Levites belong to me. 13 All the firstborn are mine - when I killed all the firstborn in Egypt, I consecrated for my own use every firstborn in Israel, whether human or animal. They belong to me. I am God."
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.