God first made a Covenant with Abraham that he and every male child should be circumcised,but would later tell of the importance of a rebellious heart turning to Him as a circumcision of the heart. It would then be a heart for Him! (Genesis 17:10,11) This is the 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.

 This all changed when Moses stayed in the mount forty days and forty nights then came back with instruction from God for the people. (Deuteronomy 10:16,17) Circumcise therefore the foreskin of your heart, and be no more stiffnecked (Rebellious). For the Lord your God is God of gods, and  Lord of lords, a great God, a mighty, and a terrible, which regardeth not persons, nor taketh  reward.

 God does not like us to have a rebellious heart (Stiffnecked) and we need to turn to him through repentance. He is a Loving God that is more than able to change a heart that is made to serve him. (Ezekiel 11:19-21) And I will give them one heart, and I will put a new Spirit within you; and I will take the stony heart out of your flesh, and will give them an heart of flesh; That they may walk in my statutes, and keep mine ordinances, and do them: and they shall be my people, and I will be their God.But as for them whose heart walketh after the heart of their detestable things and their abominations, I will recompense (Repay) their way upon their own heads, saith the Lord.

 When the people were disputing matters it was Peter who rose up and said the word of the gospel preached to the Gentiles would purify their hearts by Faith. (Acts 15:7-9) And when there had been much disputing, Peter rose up, and said unto them, Men and brethren, ye know how that a good while ago God made choice among us, that the Gentiles by my mouth should hear the word of the gospel, and believe.And God, which knoweth the hearts, bare them witness giving them the Holy Ghost, even as he did unto us; And put no difference between us and them, purifying their hearts by Faith.

 We are complete in the Body of Christ through the operation of God and not man through the baptism of the Holy Spirit who cleanses us of all sin. (Colossians 2:9-13) For in him dwelleth all the fulness of the Godhead bodily. And ye are complete in him, which is the head of all principality and power: In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead. And you, being dead in your sins and the circumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses.