Levi] Num. 10. 17, 21. work] See the Notes on v. 4. age of twenty, &c.] At twenty yeers old, the Levites were admitted into the house of God, to behold and acquaint themselves with the services thereof: at five and twenty, to assist in inferiour services, Numbers 8:24. at thirty, they bare offices, v. 3. See the Notes on Numbers 3:15. twenty yeers] Numbers 1:3.