Romans 4:11-12
Before, not after. And he received circumcision as a sign, a mark attesting the reality of the faith-righteousness which was his while still uncircumcised, that he might be the forefather of all those who believe even though they are uncircumcised--in order that this righteousness might be placed to their credit;
Matthew 22:32
I am the God of Abraham, the God of Isaac, and the God of Jacob'? He is not the God of dead, but of living men."
Romans 11:25
For there is a truth, brethren, not revealed hitherto, of which I do not wish to leave you in ignorance, for fear you should attribute superior wisdom to yourselves--the truth, I mean, that partial blindness has fallen upon Israel until the great mass of the Gentiles have come in;
Galatians 3:29
And if you belong to Christ, then you are indeed true descendants of Abraham, and are heirs in fulfilment of the promise.