John Wesley on Numbers 8:10

The children of Israel - Not all of them, which was impossible, but some in the name of all the princes or chiefs of each tribe, who used to transact things in the name of their tribes. Put their hands - Whereby they signified their transferring that right of ministering to God from the first - born in whose hands it formerly was, to the Levites, and their entire resignation and dedication of them to God's service.