A Little Yeast

"But now I am writing to you that you must not associate with anyone who claims to be a brother or sister but is sexually immoral or greedy, an idolater or slanderer, a drunkard or swindler. Do not even eat with such people. What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those outside. "Expel the wicked person from among you."  1Corinthians 5:11-13 (NIV)

God wants his church to be holy and pure. He expects our obedience in this matter. It gives God a bad name when His people knowingly live in sin. Paul also tells the Corinthians that a little yeast will leaven the whole batch of dough--in other words, sin in the church only grows. See what Francis Chan has to say in this brief video:

http://youtu.be/L6IX3opKF4A