'Circumcision' in the Bible

And he gave him the covenant of circumcision, and so he became the father of Isaac and circumcised him on the eighth day, and Isaac [did so with] Jacob, and Jacob [did so with] the twelve patriarchs.

And those believers from the circumcision who had accompanied Peter were astonished that the gift of the Holy Spirit had been poured out even on the Gentiles,

So when Peter went up to Jerusalem, those of the circumcision took issue with him,