Treasury of Scripture Knowledge
now to Abraham and his offspring were the promises made. he does not say, "to offsprings," as if he spoke of many; but as speaking of one, "and to thy offspring," which means Christ.
and he received the sign of circumcision, as a seal of the justification by that faith, which the uncircumcised have: that he might be the father of all those who believe, tho' they are uncircumcised, that it might be accounted to them also for righteousness:
Now we, my brethren, as Isaac was, are the children of the promise.