Hebrews 7:4

Melchizedek was superior to Abraham, because he took tithes from Abraham (Genesis 14:20), and he also gave him his priestly benediction (Genesis 14:19).

5-7. He is much more superior to the Levitical priests who take tithes from then Israelite brethren, but who, in Abraham their progenitor, paid tithes to Melchizedek (Hebrews 7:9).

8. He is superior to them, further, in respect that the Levitical priests are men who die. What Scripture witnesses to concerning Melchizedek is just his life. Its silence as to his family and death points to the endless life of the divine inheritor of his priesthood.

11-28. The argument now takes a further step forward, Since God promised a new priesthood (in Psalms 110), this must supersede and abolish the old. But this substitution would not have been made were it not that the old priesthood had failed to accomplish its purpose, viz. to reconcile man to God. A new covenant is therefore introduced, with Jesus as the surety for its fulfilment. It is eternal because He is eternal; and it secures salvation to the uttermost, because the Priest is One who ever liveth to intercede for those who draw near to God through Him.

11-19. The introduction of a new priesthood, and consequently of a new law, implies the imperfection of the old.