24 “This applies to the Levites: from twenty-five years old and upward they shall come to do duty in the service of the tent of meeting.
In Numbers 4:3 God’s instruction is to count the number of Levites ready for service from the age of thirty to fifty. The focus here is on the counting of the Levites above the age of thirty. In Numbers 8:24, God instructs
the Levites to serve from the age of twenty-five. A more accurate translation of the latter suggests that God permits
the Levites to serve from the age of twenty-five years old (see NKJV). This would suggest that the required age of service was not reduced as it appears in the ESV. Instead, the Levites were permitted
to serve from the age of twenty-five, perhaps for the purpose of acquiring necessary training before the required age of official service.
3 from thirty years old up to fifty years old, all who can come on duty, to do the work in the tent of meeting.