Hebrews 7:11-22 CSB
Now if perfection came through the Levitical priesthood (for on the basis of it the people received the law), what further need was there for another priest to appear, said to be according to the order of Melchizedek and not according to the order of Aaron? For when there is a change of the priesthood, there must be a change of law as well. For the one these things are spoken about belonged to a different tribe. No one from it has served at the altar. Now it is evident that our Lord came from Judah, and Moses said nothing about that tribe concerning priests.
And this becomes clearer if another priest like Melchizedek appears, who did not become a priest based on a legal regulation about physical descent but based on the power of an indestructible life. For it has been testified:
You are a priest forever
according to the order of Melchizedek.
So the previous command is annulled because it was weak and unprofitable (for the law perfected nothing), but a better hope is introduced, through which we draw near to God.
None of this happened without an oath. For others became priests without an oath, but he became a priest with an oath made by the one who said to him:
The Lord has sworn
and will not change his mind,
“You are a priest forever.”
Because of this oath, Jesus has also become the guarantee of a better covenant.
CSB: Christian Standard Bible