1 Corinthians 5:9-6:8
I wrote to you in my letter not to associate with immoral men; not at all meaning the immoral of this world, or the greedy and robbers, or idolaters, since then you would need to go out of the world. But rather I wrote to you not to associate with any one who bears the name of brother if he is guilty of immorality or greed, or is an idolater, reviler, drunkard, or robber--not even to eat with such a one. For what have I to do with judging outsiders? Is it not those inside the church whom you are to judge? God judges those outside. "Drive out the wicked person from among you."
When one of you has a grievance against a brother, does he dare go to law before the unrighteous instead of the saints? Do you not know that the saints will judge the world? And if the world is to be judged by you, are you incompetent to try trivial cases? Do you not know that we are to judge angels? How much more, matters pertaining to this life! If then you have such cases, why do you lay them before those who are least esteemed by the church? I say this to your shame. Can it be that there is no man among you wise enough to decide between members of the brotherhood, but brother goes to law against brother, and that before unbelievers? To have lawsuits at all with one another is defeat for you. Why not rather suffer wrong? Why not rather be defrauded? But you yourselves wrong and defraud, and that even your own brethren.