A.T. Robertson Commentary Hebrews 7:22

"by so much also hath Jesus become the surety of a better covenant." — Hebrews 7:22 (ASV)

By so much also (κατα τοσουτο κα). Correlative demonstrative corresponding to καθ' οσον (the relative clause) in verse 20.

The surety (εγγυος). Vulgate sponsor. Old word, here only in the N.T., adjective (one pledged, betrothed), from εγγυη, a pledge, here used as substantive like εγγυητης, one who gives a pledge or guarantee. There may be a play on the word εγγιζω in verse 19. Εγγυαω is to give a pledge, εγγυαλιζω, to put a pledge in the hollow of the hand. It is not clear whether the author means that Jesus is God's pledge to man, or man's to God, or both. He is both in fact, as the Mediator (ο μεσιτης, 8:6) between God and man (Son of God and Son of man).