i don't understand "the priesthood changed from Levi to Judah" -- if i'm understanding Hebrews correctly, His priesthood like Melchizadek is not by genealogy, so not transferred to another tribe - but by the direct appointment of God.
who appointed Christ, and appointed us to be found in Him. so we take part in it - but He is eternal, eternally our High priest.
He sent His Christ to be born into Judah, to rightfully be heir to the throne over Israel, but He became our priest apart from any relationship to a tribe, right?
i guess it is - the priesthood is changed. it isn't the same priesthood that Levi was appointed to.
i don't want to get into any argument about the original language of this epistle. am totally not qualified. prolly not really pertinent to the topic, but i really don't know. poking around, there is actually serious discussion about that i found on some other forums - interesting stuff that is way over my head, haha.