Circumcision is a ritual.   It may have some health benefits but it NEVER made an individual acceptable to the Lord.   

The way the Law worked was that you were blessed as long as you kept it.   If you broke the law you were rejected and cursed.   
Everyone, except Jesus, broke the Law and so the Law cursed them.   

So, every tenet of Judaism was reflected in circumcision as it is the most basic requirement for acceptability.   

Today we have Christians who believe
   ➛ you must worship on Saturday
   ➛ you must abstain from alcohol
   ➛ you must wear modest clothes
   ➛ you must be Water Baptized
   ➛ you must partake of Communion
   ➛ you must repent every time you sin
   ➛ you must attend church
   ➛ you must pay tithes
   ➛ etc.   

Every one of these requirements is Of The Circumcision in spirit.   

Of The Circumcision is Another Gospel.   The preachers of Another Gospel are accursed as far as Paul is concerned.   

And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Spirit. Act 10:45 Of The Circumcision refers to those believers who were still steeped in Judaism.     Such did not understand the parables of Jesus referring to new wine and new cloth.     Mat 9:16,17 Faith in Christ Jesus results in being born as a New Spirit being.     It is the creation of new cloth, new wine skin.     The new cloth should not be mingled with old cloth.     The new wine skin is for new wine.     That `new wine` is the Holy Spirit.      Paul makes a very serious point about Another Gospel in Gal 1:8,9 where he is addressing the same people whom Jesus forbade from mingling old cloth with new and from putting new wine in old bottles Mat 9:17,18 and the same people to whom the entire book of Hebrews is addressed and summarized in Heb 10:26.

And when Peter was come up to Jerusalem, they that were of the circumcision contended with him, Act 11:2 Religion crops up in the middle of revival.     Imposition of religion is always by the enemy who resists the Truth and the Holy Spirit.      In the defense of the beleivers in jerusalem, they had been raised from birth to be religious.

And the father of circumcision to them who are not of the circumcision only, but who also walk in the steps of that faith of our father Abraham, which he had being yet uncircumcised. Rom 4:12 Adherence to the Mosaic Covenant is optional meaning that it is not required, meaning that it adds nothing to the righteousness of Grace Through Faith.

Now I say that Jesus Christ was a minister of the circumcision for the truth of the Lord, to confirm the promises made unto the fathers: Rom 15:8 Jesus fulfilled the Law of which part of it was to confirm the promises made to all the Old Testament saints.

But contrariwise, when they saw that the gospel of the uncircumcision was committed unto me, as the gospel of the circumcision was unto Peter; Gal 2:7 They were convinced that the ministry of uncircumcision had been given to Paul.

(For he that wrought effectually in Peter to the apostleship of the circumcision, the same was mighty in me toward the Gentiles:) Gal 2:8 Paul points out that Peter`s preaching of the hybrid gospel had some effect but that Paul`s ministry was mighty toward the gentiles.     The implication is that the Holy Spirit accomplished much more in Paul because He promotes the Gospel of liberty.

For before that certain came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them which were of the circumcision. Gal 2:12 Peter was a tad political about Judaism and Grace depending on who he was with.

And Jesus, which is called Justus, who are of the circumcision.     These only are my fellowworkers unto the kingdom of heaven, which have been a comfort unto me. Col 4:11

For there are many unruly and vain talkers and deceivers, specially they of the circumcision: Tit 1:10 Teachers must be rooted in the Gospel of Grace Through Faith.     Hybrid gospel is no gospel at all.