{By so much also} (kata tosouto kai). Correlative
demonstrative corresponding to kath' hoson (the relative
clause) in verse  20 . {The surety} (egguos). Vulgate
_sponsor_. Old word, here only in the N.T., adjective (one
pledged, betrothed), from eggu(885c), a pledge, here used as
substantive like eggu(8874)(8873), one who gives a pledge or guarantee.
There may be a play on the word eggiz(935c) in verse  19 . Eggua(935c)
is to give a pledge, eggualiz(935c), 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 (ho mesit(8873),  8:6 ) between God and man
(Son of God and Son of man).