Hebrews 7:8
7:8 and in one case tithes are received by mortal men, while in the other by him who is affirmed to be alive.
Hebrews 7:28
7:28 For the law appoints as high priests men subject to weakness, 1 but the word of solemn affirmation that came after the law appoints a son made perfect forever.
1 sn See Heb 5:2 where this concept was introduced.