Numbers 1:47-54

When a census of the tribe of Levi takes place. Numbers 3:15; Numbers 26:62, “all” the males are counted from a month old and upward, and not, as in the other tribes, those only who were of age for service in the field.

Numbers 1:48

had spoken - Render spake. The formal appointment is only now made, in reward for their zeal Exodus 32:26, though reference to their future office appears previously in Leviticus 25:32 ff, and they had already acted as assistants to the priests (compare Exodus 38:21).