The Law is quite clear that the descendants of Aaron are the only ones allowed to burn incense before YHWH:
"Reminder to sons of Israel, to purpose which man, alien, shall not
near to fume incense to faces of YHWH, which he [is] not from seed of
Aaron, and he shall not be as Korah..." - Num 16:40.
That being as
it is, how could any other priesthood be perceived to take precedence
over the Torah or otherwise be imposed on the Torah? Enforcing a
"priesthood of Malkizedeq" (cited by one theologian in the NT) amounts
to an attempt at finding a presumed loophole in the text, such as by
citing psalms or using other works. By the standard of the actual
Torah, there is no priesthood aside from Aaron and his descendants.
Later prophets are forbidden to nullify the commandments, so an author
claiming no inspiration would have no basis either.
