John was equally direct -
Mat. 3:7 But when he saw many of the Pharisees and Sadducees coming to where he was baptising, he said to them: ‘You brood of vipers! Who warned you to flee from the coming wrath? 8 Produce fruit in keeping with repentance. 9 And do not think you can say to yourselves, “We have Abraham as our father.” I tell you that out of these stones God can raise up children for Abraham. 10 The axe has been laid to the root of the trees, and every tree that does not produce good fruit will be cut down and thrown into the fire.
Seems as if being genuine physical descendants of Abraham, complete with family tree, was worse than worthless for those who trusted in their pedigree rather than in humble faith.
Peter was more positive in his approach to those who trusted in Moses -
Acts 3:22 For Moses said, “The Lord your God will raise up for you a prophet like me from among your own people; you must listen to everything he tells you. 23 Anyone who does not listen to him will be completely cut off from their people.”
- those trusting in circumcision rather than Christ will be completely cut off - separated from the redeemed people of God.
Peter continues, to show that the Abrahamic covenant is fulfilled in & by Christ -
24 ‘Indeed, beginning with Samuel, all the prophets who have spoken have foretold these days. 25 And you are heirs of the prophets and of the covenant God made with your fathers. He said to Abraham, “Through your offspring all peoples on earth will be blessed.” 26 When God raised up his servant, he sent him first to you to bless you by turning each of you from your wicked ways.’
The OP thesis is completely at variance with Scripture.