Brethren we are to circumcise our children on the eighth day; which is an allegory of spiritual circumcision. Only adult converts who are circumcised in heart being more than eight days old are not required to be physically circumcised. In the millennial kingdom there shall be no uncircumcised person allowed to enter the temple.
Ez 44:9 Thus saith the Lord God; No stranger, uncircumcised in heart, nor uncircumcised in flesh, shall enter into my sanctuary, of any stranger that is among the children of Israel.
7:8 And he gave him the covenant of circumcision: and so Abraham begat Isaac, and circumcised him the eighth day; and Isaac begat Jacob; and Jacob begat the twelve patriarchs.