Eleazar is joined in commission with Moses in the service; and the method of enumerating them is, as was before appointed, on their coming forth from Egypt at Mount Sinai. Numbers 1:1-3.
Related Commentaries of Numbers 26:3
Numbers 26:3-4
3 And Moses and Eleazar the priest spake with them in the plains of Moab by Jordan near Jericho, saying,
4 Take the sum of the people, from twenty years old and upward; as the LORD commanded Moses and the children of Israel, which went forth out of the land of Egypt.