Christ is the true offspring (seed) of Abraham (Galatians 3:16), the one who fulfilled the original redemptive promise given in Genesis 3:15. He is the only one who has the right to inheritance (life in God’s presence, Galatians 3:18). Those united to him by faith are also offspring of Abraham (Galatians 3:29) in the sense that they get to share in the inheritance that Christ has won (Galatians 3:26). The true offspring of Abraham are thus those who have faith, not those who can trace physical descent.1
29 And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise.