This is about peter not accepting gentiles he gets his vision later on , the law is replaced updated the circumcision became the baptism the circumcision still exist but in a different form this means to fulfill if there was nothing in return then there would be a problem because then its destroyed
This was actually a educated guess but i can confirm with scripture
Colossians 2
8Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ. 9For in him dwelleth all the fulness of the Godhead bodily. 10And ye are complete in him, which is the head of all principality and power: 11In 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: 12Buried 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