First Corinthians 5:6 warns that tolerating a serious sin in the church is dangerous, because a little sin can spread through the whole community just as a small amount of yeast works through a batch of dough. Paul is confronting a congregation that is proud of its tolerance for a man living in a sexual relationship with his father’s wife, and he uses a common kitchen image to show why that pride is misplaced. He writes to the believers in Corinth, a church he had founded, while he is absent from them in body but present in spirit.
Your boasting is not good. Don’t you know that a little yeast leavens the whole lump?
1 Corinthians 5:6 (WEB)
What 1 Corinthians 5:6 Means
Paul begins with the word “boasting,” which tells you the Corinthians were not simply unaware of the problem. They were proud of how open-minded or generous they appeared, as though allowing the offender to remain in fellowship showed grace. Paul says that this pride is “not good,” meaning it is not a fitting response to what has happened among them. The rhetorical question that follows, “Don’t you know?”, assumes they should already grasp a basic principle of ordinary life.
The principle is the image of yeast. A small amount of leaven, mixed into dough, gradually works through the entire lump. Paul is not saying that every sin inevitably corrupts a church beyond repair, and he is not promising that a tolerated sin will always produce a visible collapse. He is saying that unchecked wrongdoing tends to spread in its influence, shaping attitudes, excusing behavior, and changing what a community considers normal.
The Context of 1 Corinthians 5:6
First Corinthians is a letter written by the apostle Paul, probably in the middle of the first century, to a church in the Greek city of Corinth. That church was rich in spiritual gifts but also divided, prideful, and quick to excuse conduct that the wider pagan world would have found shocking. Chapter 5 deals with a specific case of sexual immorality that was known even among outsiders, and Paul’s instruction is to address it openly rather than look the other way.
The verses just before and after set the tone. In verses 3 through 5, Paul describes a formal judgment in which the offender is removed from the community in the hope that his spirit might be saved in the day of the Lord. Verses 7 and 8 then move straight from yeast to the Passover, calling the church to “purge out the old yeast” and to keep the feast with sincerity and truth. Read with these lines around it, the verse is not a general comment about sin in the abstract but a pastoral call to a specific community to clean house for the sake of its own health and its witness.
Key Phrases in 1 Corinthians 5:6
Galatians 5:9
A little yeast grows through the whole lump.
(WEB)
Paul uses the same yeast image in Galatians, where he warns that a little false teaching can spread through the church. The parallel shows that his concern about leaven runs across his letters and applies to doctrine as well as conduct.
1 Corinthians 5:7
Purge out the old yeast, that you may be a new lump, even as you are unleavened. For indeed Christ, our Passover, has been sacrificed in our place.
(WEB)
This verse continues directly from the passage and calls the church to purge out the old yeast so that they can be a new lump. It explains the purpose behind the warning, which is renewal in Christ rather than condemnation alone.
A Short Prayer From 1 Corinthians 5:6
Lord, you see the places in my life where I have grown comfortable with things I should confront. Show me where pride or quiet tolerance has taken root, and give me the honesty to name it. Help me to be part of a community that loves the truth enough to address what harms us, and let my own life be kept in sincerity and truth. Make me faithful to clean out what does not belong, for the sake of your name and the good of those around me. Amen.
