First Corinthians 5:6 teaches that tolerating a sin the church has ignored is dangerous, because a small amount of unchecked wrongdoing spreads through the whole community, much as a little yeast works through an entire batch of dough. Paul is correcting a congregation that was proud of how it handled a serious case of sexual immorality among its members. The words come from the apostle Paul, who wrote this letter to the church in Corinth, a busy port city with a mixed population and a church that had its share of divisions.
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 by saying the Corinthians’ “boasting” is “not good.” They seem to have been congratulating themselves about their tolerance or openness, when in fact the situation called for grief and corrective action. He is not praising their broad-mindedness. He is pointing out that their pride has blinded them to what the sin was doing inside the congregation.
The image of yeast is the heart of the verse. Yeast is a small amount of leaven that, once mixed into dough, works its way through the whole lump. Paul is saying that sin does not stay contained. A small compromise, if left alone and treated as harmless, will change the character of the whole church over time.
The verse does not promise that every hidden sin will instantly show itself, nor does it say that the church should become suspicious of everyone. It is a warning about what happens when a community refuses to address a clear wrong and instead celebrates its own generosity.
The Context of 1 Corinthians 5:6
First Corinthians was written by Paul to a church he had founded, responding to reports of quarrels, lawsuits between believers, and moral failures. Chapter 5 deals with a man who was living with his stepmother, a situation that even the surrounding pagan culture found shocking. Paul had already judged the matter and urged the church to act together in the name of the Lord Jesus.
Just before verse 6, Paul describes a difficult step of separating the offender from the fellowship for the sake of his own repentance and the health of the body. Just after it, he moves into the image of the Passover, calling the church to clean out the old yeast and keep the feast with sincerity and truth. Read in that setting, the yeast saying is not a general remark about sin. It is part of a pastoral call to discipline and purity within a community that belongs to Christ.
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 corrupt a whole community. Reading the two passages side by side shows that Paul saw leaven as a recurring picture of how error and sin move through the church.
1 Corinthians 5:7-8
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. 8 Therefore let us keep the feast, not with old yeast, neither with the yeast of malice and wickedness, but with the unleavened bread of sincerity and truth.
(WEB)
These verses are the immediate next step in Paul’s argument, calling believers to clean out the old yeast because Christ has been sacrificed. Together with verse 6, they show that the warning about sin is rooted in the good news of what Christ has already done.
A Short Prayer From 1 Corinthians 5:6
Lord, you see the small compromises I have been tempted to excuse, and you see how they can slowly shape my heart and the people around me. Help me to take sin seriously, not with pride or harshness, but with honesty before you. Give me the courage to speak truth in love when I see wrong in my church, and the humility to examine my own life first. Make me part of a community that is being made new, and let my life reflect the sincerity and truth that belong to you. Amen.
