Genesis 17:14

And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut oft from his people; he hath broken My covenant. Thus circumcision was a sacrament, a means of grace, in the Old Testament, a rite through which the Lord transmitted the blessings of His covenant to the children of Abraham. Its provisions were simple, the act itself being plainly indicated, the purpose being the sign of the covenant, the time being eight days, or the eighth day after birth, the extent making it include not only male children, but also slaves, both those born in the master's home and those bought elsewhere, and the inviolability of the act being such as to cause every male that had not submitted to this provision of the covenant to be cutoff by an act of divine judgment or by an early death. The significance of the sacrament consisted in this, that the descendants of Abraham were to circumcise the foreskin of their hearts, be a holy people unto the Lord, Deuteronomy 10:16. But above all, circumcision was the seal of the righteousness of faith, Romans 4:11, and a type of Holy Baptism, the corresponding sacrament of the New Testament. Through the water of Baptism, as an external sign, the righteousness of God, the forgiveness of sins, is sealed unto us.