Titus 3:9-11

But avoid stupid and foolish controversies and genealogies and dissensions and wrangling about the Law, for they are unprofitable and futile. [As for] a man who is factious [a heretical sectarian and cause of divisions], after admonishing him a first and second time, reject [him from your fellowship and have nothing more to do with him], Well aware that such a person has utterly changed (is perverted and corrupted); he goes on sinning [though he] is convicted of guilt and self-condemned.