In Genesis 17:7 we see God declaring his intent to establish an EVERLASTING agreement between himself and Abram and his descendants. "And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee".
This agreement is to be witnessed to by the removal of the foreskin.
Genesis 17:10-11 This [is] my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised. And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.
Those without this mark are excluded from the agreement and the blessings associated with it.
Genesis 17:14 And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant.
How then can Galatians 5:6 be resolved? "For in Jesus Christ neither circumcision availeth any thing, nor uncircumcision; but faith which worketh by love. "
Squaring this circle opens ones eyes to the existence of a transcendent state of grace.