The Priestly source and the Blessing of Moses, which critical scholars view as originating centuries later, portray the Levites firmly established as a tribe, and as the only tribe with the right to become priests.
Was Levi a priest?
Thus, Levi was an ideal priest, who had been granted a covenant with YHWH, and the Malachi passage emphasizes the postexilic view that the entire priesthood was subsumed under the genealogy of Levi as its first ancestor; all priests had to claim Levitical descent, in order to be accepted for their office, which was ...
Why were the Levites not counted?
Later in the story, as presented in the Pentateuch, Levi and his family, the Levites, are not numbered with the other tribes (Numbers 1:17–46). ... Since the Levites have no land, they are allotted a tithe to sustain themselves while they work as priests (Numbers 18:21, 24).