'Circumcision' in the Bible

And he gave him the covenant of circumcision: and so Abraham begat Isaac, and circumcised him the eighth day; and Isaac begat Jacob, and Jacob the twelve patriarchs.

And they of the circumcision that believed were amazed, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Spirit.

And when Peter was come up to Jerusalem, they that were of the circumcision contended with him,