Numbers 3:22
from a month old: The males of all the other tribes were numbered from twenty years old and upwards; but, had the Levites been numbered in this way, they would not have been nearly equal in number to the first-born of the twelve tribes. Add to this, that as there must have been first-born of all ages in the other tribes, it was necessary that the Levites, who were to be their substitutes, should also be of all ages; and it appears to have been partly on this ground, that the Levites were numbered from a month old and upwards. Num 4:38-40 Reciprocal: Num 3:15 - General Num 3:39 - and Aaron Num 4:44 - General Jos 21:6 - General