Romans 4:11

11 aHe received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised. The purpose was bto make him the father of all who believe without being circumcised, so that righteousness would be counted to them as well,

Galatians 3:7

7Know then that it is cthose of faith who are dthe sons of Abraham.

Galatians 3:16

16Now ethe promises were made fto Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, gAnd to your offspring,” who is Christ.
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