Read 1 Corinthians 5:6-13.
Sin in the church is not only about the sinner; it affects everyone. The Corinthians had an unrepentant sinner in their ranks, and rather than dealing with the sin, they were tolerating it (see 1 Corinthians 5:1-2). Paul said they were even "boasting" about it (v. 6)! This one person's sin was changing the whole church; in pride, they were now calling "good" what God called "evil."
Christians must see sin for what it is—the way to bondage and death—so that we cling to Christ.
Paul compares sin in the church to yeast in a lump of dough. In Exodus, when the Israelites were leaving Egypt, God told them not to leaven their bread—there was no time because their rescue was coming quickly. Even now, at Passover many Orthodox Jews will search for any yeast in the house to get rid of it. It's a symbolic ritual: Yeast represents the old way of life under slavery. The Corinthian Christians were never slaves in Egypt, but they were once slaves to sin—until Christ set them free. That is why Paul told them to get rid of the "yeast," the sin in their midst.
So seriously did Paul want these believers to treat sin that he desired them not to associate with or even share a meal with unrepentant sinners in the church (see 1 Corinthians 5:9, 11). Christians must see sin for what it is—the way to bondage and death—so that we cling to Christ, humbly rejecting sin and living in the freedom He has won for us.
Prayer: Lord, help me to see the sin in my life, that I might repent, remembering the freedom You have purchased for me with Christ's blood. Help me to walk humbly before You in righteousness. I pray in the name of Jesus. Amen.
"Your boasting is not good. Don't you know that a little yeast leavens the whole batch of dough?" (1 Corinthians 5:6).