Verses 1-13 - There was much work belonging to the priests' office, and there wer now only Aaron and his two sons to do it; Godappoints 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 unde further obligations to serve him faithfully. God's right to us by redemption, confirms the right he has to us by creation.