Circumcision does not apply to Gentiles under the New Covenant in Christ Jesus. Acts 15 made it clear. Jews if they were to believe in Christ are still expected to be circumcised. The circumcision covenant was made with Abraham and the Hebrew people. This covenant does predate the Mosaic Law (Genesis 17:10-14).
This is the reason Paul needed to have Timothy circumcised, because Timothy was of Hebrew descent and as such needed to be circumcised under the Abrahamic covenant.
This is why Paul could write in Romans chapter 4:
" Does this blessedness then come upon the circumcised only, or upon the uncircumcised also? For we say that faith was accounted to Abraham for righteousness. 10 How then was it accounted? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised. 11 And he received the sign of circumcision, a seal of the righteousness of the faith which he had while still uncircumcised, that he might be the father of all those who believe, though they are uncircumcised, that righteousness might be imputed to them also, 12 and the father of circumcision to those who not only are of the circumcision, but who also walk in the steps of the faith which our father Abraham had while still uncircumcised."
The circumcision was not abolished but is simply not necessary for Gentiles under the New Covenant.
"And they said to him, “You see, brother, how many myriads of Jews there are who have believed, and they are all zealous for the law; 21 but they have been informed about you that you teach all the Jews who are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children nor to walk according to the customs. 22 What then? The assembly must certainly meet, for they will hear that you have come. 23 Therefore do what we tell you: We have four men who have taken a vow. 24 Take them and be purified with them, and pay their expenses so that they may shave their heads, and that all may know that those things of which they were informed concerning you are nothing, but that you yourself also walk orderly and keep the law. 25 But concerning the Gentiles who believe, we have written and decided that they should observe no such thing, except that they should keep themselves from things offered to idols, from blood, from things strangled, and from sexual immorality.” (Acts 21:20-25).
The New Testament Church didn't preach than the Hebrews would not need to be circumcised anymore (It was still a commandment for them - the 144,000, selected from among the 12 tribes of Israel, were surely all circumcised and they were expected to be so), but rather the apostolic Church emphasized that circumcision was not a commandment given to the Gentiles under the New Covenant.
