Hebrews 7:20-24
7:20 And since this was not done without a sworn affirmation – for the others have become priests without a sworn affirmation,
7:21 but Jesus did so with a sworn affirmation by the one who said to him, “The Lord has sworn and will not change his mind, ‘You are a priest forever’” –
7:22 accordingly Jesus has become the guarantee of a better covenant.
7:23 And the others who became priests were numerous, because death prevented them from continuing in office,
7:24 but he holds his priesthood permanently since he lives forever.