The covenant of circumcision (diaqhkhn peritomh). A covenant marked by (genitive) circumcision (no article) of which circumcision is the sign ( Romans 4:11 ) as set forth in Genesis 17:9-14 . In the ancient Greek diaqhkh was usually will (Latin, testamentum) and sunqhkh was used for covenant (sun, together, rather than dia, between). But the LXX and the N.T. use diaqhkh for covenant (will in Hebrews 9:15 ) as Lightfoot on Galatians 3:16 says: "The LXX translation and New Testament writers probably preferred diaqhkh as better expressing the free grace of God than sunqhkh." And so (kai outw). After the covenant was made and as a sign and seal of it.