Purge The Leaven For Purity—1 Corinthians 5:6-8


Levi Durfey




Last time we saw that there was a man in the Corinthian church who was living with, sleeping with his stepmother. Instead of speaking out against the sin, the church instead boasted in the man’s sin. 


Perhaps they thought it was his Christian liberty to do so, or perhaps they thought it was an expression of Christian love. 


There are times and places for liberty and love, of course, but not when the sin is so obvious and so corrupting of others in the church.


Paul called upon the church to discipline him by removing him from their presence. The goal of this discipline was to hopefully to see the man come to his senses and repent and be “saved in the day of the Lord Jesus.” 


In verses 6-8, Paul gives a foundational principle for his command in verses 1-5 to expel the man—


6 Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? 7 Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us: 8 Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth. (1 Corinthians 5:6–8)


Paul used the idea of “leaven” to illustrate this principle; today we might say…




1 Corinthians 5:6 Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? 


A. The Ancient Use Of Leaven


The word “leaven” (ζύμη, NNSF, ζύμη)—refers to a bit of bread dough that has yeast in it. Yeast is what causes bread dough to rise. 


In ancient times, you couldn’t buy yeast in the store. You had to leave dough out for several days to “catch” the yeast spores from the air. 


After you got some dough with yeast in it, you would save a part of it for the next day’s batch of dough—that piece was called leaven. 


The next time you made bread, you would mix in the small bit you saved with the new dough and it would spread throughout the whole lump of new dough.


1 Corinthians 5:7a Purge out therefore the old leaven, that ye may be a new lump…


“Purge out” (ἐκκαθάρατε, VAAM2P, ἐκκαθαίρω) means to remove something that is unclean or to cleanse something. 


When Paul called Christians to “Purge out therefore the old leaven,” he was thinking of the Feast of Unleavened Bread, which was a week-long feast that took place immediately after Passover.


To prepare for the Feast of Unleavened Bread, the Israelites would purge every last piece of leaven from their homes. 


We’ll see that this had a figurative meaning, but it also could have been a health-related issue. Reusing a bit of bread dough over and over like that would increase the dangers of infection. So once a year, the Israelites would start their bread-making over from scratch. 


(See, Gordon D. Fee, The First Epistle to the Corinthians, The New International Commentary on the New Testament, [Grand Rapids, MI: Wm. B. Eerdmans Publishing Co., 1987], 216)


B. The Figurative Meaning Of Leaven


Paul, however, is not referring to leaven as a bit of bread dough. He is using the word “leaven” figuratively. What does “leaven” mean figuratively in the Bible? With the exception of one debatable passage (Matthew 13:33; Luke 13:21), “leaven” refers to sin and evil when it is used figuratively in the Bible.


For example, Jesus told his disciples to “beware of the leaven of the Pharisees and of the Sadducees” (Matthew 16:6). Comically, the disciples thought that Jesus was talking about bread dough. So Jesus explained it and…


12 Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees. (Matthew 16:12)


In this case, it was the teaching of the Pharisees and Sadducees that was evil. Of course, when someone teaches, it spreads to others (unless they are a really bad teacher), so it was like leaven working it’s way throughout the whole lump.


In 1 Corinthians 5, Paul was saying that the Corinthian’s “glorying” (or boasting) in the sin of the man sleeping with his stepmother was like leaven. 


When Christians start boasting in sin (by calling it Christian liberty or loving tolerance, for example), it will spread like leaven throughout the whole church.


Are there sins in your life or in the life of other Christians that you boast about? Sins that you justify by calling them Christian liberty? Let’s look at some…




1 Corinthians 5:7 Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us: 


A. We Ought To Live Like Who We Are


Look at the word, “unleavened” (ἄζυμοι, JNPM, ἄζυμος)—Just as leavened bread is symbolic of sin and evil, so unleavened bread (think of a flat cake) is symbolic of purity and truth.


We are to purge out the old leaven “that ye may be a new lump, as ye are unleavened.”


It sounds like Paul just contradicted himself. Purge sin from yourselves so that you may be a new, pure church, because you are unleavened—you are without sin and evil. How can both be true?


There is a theme of newness that runs through the New Testament, perhaps the most famous verse about newness is…


17 Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new. (2 Corinthians 5:17)


We look at that verse and wonder, after having a fight with our spouse and our kids while trying to get to church, “Am I really a new creature? It seems that I have a lot of old things still in me!”


Yes, in God’s eyes, you are a new creature—not because of what you have done, but because of what Jesus Christ has done for you. Look at the next chapter in 1 Corinthians—


9 Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, 10 Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God. 


11 And such were some of you: but ye are washed, but ye are sanctified [set apart, made holy], but ye are justified [declared right in God’s sight] in the name of the Lord Jesus, and by the Spirit of our God. (1 Corinthians 6:9–11)


We call this in theology, “Positional Sanctification,” because it is as if God when looks at us, he sees his Son Jesus standing in our position. Paul is saying to us that we are “unleavened;” we are pure and holy in God’s sight.


And since we are pure and holy in God’s sight, we are to live like it. We are not supposed to allow evil and sin within us. We are to purge ourselves of such things, and live out our newness or positional sanctification in our daily lives.


We are supposed to become in daily life as we really are in God’s sight. Believers are made new by sheer grace and mercy. We also become that newness in our lives by grace and mercy.


Suppose you are given a brand-new car—did you make the car new? No, a manufacturer did, you only received it. 


It’s the same with our salvation, we don’t make our salvation—we only receive it as a gift. When you are saved, God makes you a new creature—a new creation.


Now, you drive the car for a few days, and it gets all muddy and dirty. Is it not a new car any longer? Of course it’s a new car, you’re still trying to figure out how to work the radio! It’s still a new car in your eyes.


In the same way, a Christian is still a new creation in God’s eyes even after sinning. No matter how much sin you do, you’ll always be a new creation in God’s eyes.


I am not much for washing my vehicles—Dad always said that it would just make them rust faster, I guess that rubbed off on me. That’s probably why our vehicles are both white—white goes with any color of mud!


But when you have a new car, you want to keep it clean. You take it to the car wash often and get it all spiffy.


In the same way, a true Christian doesn’t want sin on them. We go and we ask forgiveness, and God “…is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness” (1 John 1:9).


That is what Paul is telling us to do in 1 Corinthians 5:7—we are unleavened bread (we’re new creations), so we need to, we should want to, purge ourselves of the leaven of sin that gets in us, whether as an individual or a community. 


We should want to live as we really are in God’s eyes.


A second motivation that Paul gives us for purging sin from our lives is…


B. We Ought To Remember That Christ Is Our Passover Lamb


He says we should purge out the old leaven…“For even Christ our passover is sacrificed for us:” 


The Passover takes us back to Exodus, when the Israelites were about to be freed from Egypt, right before the final plague on Egypt—the death of all the firstborn. 


A terrible thing to be sure, but God gave a way of escape for whoever would take it. They were to kill a lamb and then spread it’s blood on the doorposts. If they had faith in God to protect them, they would do this. We read in Exodus—


12 For I will pass through the land of Egypt this night, and will smite all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD. 13 And the blood shall be to you for a token upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt. 14 And this day shall be unto you for a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever. (Exodus 12:12–14)


After the Passover Feast, starting the next day, the Jews would then celebrate the Feast of Unleavened Bread for the next week (Exodus 13:7). So you see how this idea of passover and unleavened bread are connected.


Now, as Christians, Christ is our  “passover” lamb. The blood of the lamb sprinkled on the doorposts saved the Israelites from the destroying angel (who was securing God’s justice on the Egyptians). 


So, in the same vein, having faith in Christ and his work shedding his blood as a lamb on the cross gives us salvation from God’s rightful justice against our sins. 


This is really what salvation is all about, by the way. We want to emphasize the idea of going to Heaven or how Jesus can give us a better life—but really salvation is about escaping God’s justice on our sins. 


That’s why the Bible uses a word like “justified” to describe our salvation. Justified is being declared right in God’s sight. Are you justified before God today? Do you have faith in Jesus Christ?


23 For all have sinned, and come short of the glory of God; 24 Being justified freely by his grace through the redemption that is in Christ Jesus: (Romans 3:23–24)


When the Passover lamb was slain, that was when the Israelites were required to purge the leaven from their homes in preparation for the seven-day Feast of Unleavened Bread.


In the same manner, we ought to want to purge sin from our lives as Christians. If we don’t want to purge our sin, it’s evidence that something is wrong. The Christian should want to live their life differently, as a testimony, as a celebration of what Jesus has done for us.




1 Corinthians 5:8 Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.


A. The Christian Life Is A Feast Of Celebration…


What is Paul talking about when he says, “let us keep the feast” (ἑορτάζωμεν, VPAS1P, ἑορτάζω)?


Some people immediately assume that Paul is talking about the Lord’s Supper here, and it’s possible that he is. 


However, not every use of an concept or word in the Bible means the same thing. Mentioning water, for example, doesn’t automatically mean that baptism is what is being talked about.


Just because he has mentioned leavened and unleavened bread does not mean that he is talking about the Lord’s Supper when he refers to a “feast.”


One reason I think that is the case here is that “let us keep the feast” is in the present tense, indicating a continuous action. It’s something that we’re doing all the time, not something that we do only when we’re together to worship.


The Christian life itself is a “feast” or a “celebration” of what Jesus bought for us as our Passover lamb. It’s another way of saying the Christian life is to be a testimony of what Christ did for us on the cross.


The Christian Life Is A Feast Of Celebration…


B. Kept Not With Malice And Wickedness


We are to live our lives “not with old leaven [the old, sinful, worldly way of doing things], neither with the leaven of malice and wickedness.”


Why does Paul focus on the vices of “malice and wickedness” (κακίας καὶ πονηρίας)? Because “malice and wickedness” are general terms that refer to all sorts of sin and evil that someone could do. 


These are root issues that we are to avoid as we live out the feast of the Christian life. Look at it this way—why do we commit adultery, lie, or steal? Because there is a root of malice of wickedness growing inside us.


The Christian Life Is A Feast Of Celebration Kept Not With Malice And Wickedness…


C. But With Sincerity And Truth


The word “sincerity” (εἰλικρινείας, NGSF, εἰλικρίνεια) refers to purity and transparency. When a person is sincere, it’s like the sun shines through them—you can tell that they are who they say they are; nothing is hidden away.


For a person to be described as “truth,” they would have a heart that corresponds to the truth of the Bible, which in turn, corresponds to the character of God.


Both these words refer to what happens inside our hearts—our deepest attitudes and motives. The Christian’s life will be pure and sincere when it is based on the truth of God’s Word. 


One more thought about “sincerity and truth” that I wish would be heeded by those calling themselves Christians today. It isn’t enough to say that you love the “truth,” but live lives that contradict the truth that you profess. 


In the sincere Christian, God’s truth is both believed and lived out in daily life. There’s none of this loving the Lord on Sunday and living like the devil the rest of the week.


The Christian’s life is to be a celebration feast that honors what Jesus Christ did to save us.




One of my friends in Minnesota had a vivid illustration about not allowing sin to remain in a person’s life. I’ve never been able to forget it—you’ll see why.


Suppose you have a pan of brownies—they taste good, right? Yummy. You want to eat it. Now, suppose in the middle of the pan of brownies you discovered a lump of poop. The cat thought it was his litter box! 


How do you feel about the pan of brownies now? Do you cut out the offending piece and eat the rest? No! You’d be tossing that whole pan into the garbage!


A little leaven—or poop—spoils the whole batch. Christians shouldn’t allow sin to enter into their lives.


Now, while I’ve always remembered that illustration, and I agree with the principle it illustrates, I don’t think it’s completely accurate.


There’s a certain sense that we have to tolerate sin in our lives at least to some degree. Otherwise we wouldn’t watch anything or do anything.


Even old TV shows like Andy Griffith or Hogan’s Heroes have sin in them. A grocery store has magazines with sinful pictures on the cover (and I am not talking about chocolate!). A coworker might utter a bad word now and then or drink beer. The friends at coffee might gossip about someone.


Some Christians concerned about sinful influence have gone to the extreme of isolating themselves—even from a church because they don’t want to be around people who sin at all (or at least the sins they disapprove of).


Some churches have disciplined church members for every kind of sin they can think up—red dresses, listening to country music, reading a worldly newspaper, and so on.


This chapter here helps us—the sin that Paul wanted the man sleeping with his stepmother disciplined for was, in fact, a serious sin corrupting the church. 


It wasn’t that there was a potential or a fear of sin spreading, it was spreading—they were prideful about it. It was time to cut out the leaven. It was a serious, obvious sin—not debatable by any measure. Clearly stated in God’s Word.


Let’s go back to our pan of brownies—suppose instead of a lump of poop being in the middle of the pan, it was a lump of garden dirt. What would you do then? I would have no problem cutting the dirt out and eating the rest of the brownies! 


There are sins that we can tolerate in our lives, because we’re mature enough to ignore and overlook them…there’s little danger of them spreading to us. 


Because Colonel Hogan kisses Helga and shares a drink with Colonel Klink while deceiving him into going along with a plan to blow up a train doesn’t mean that we’ll do the same. 


Why? Because we can cut out dirt lumps and enjoy the rest.


But, if you wake up at night and the woman that comes into your mind is the half-naked actress from a show you watched that evening—well, then you are dealing with a leaven kind of sin and it is going to spread. 


You need to cut out that show or at least have your wife say—“Honey, go check the kids”—when those kinds of scenes come on.


If you find yourself desiring a beer to relax, you’ve probably entered a state of dependence, and it won’t take but a stressful day to push you into drunkenness. Purge the leaven from your life completely.


If you find yourself saying words you shouldn’t, or thinking about saying those words, then, it’s time to find the leaven that is spreading that sin into your life and cut it out.


Your life, my fellow Christian, is to be a celebratory feast for what Jesus Christ did for you—don’t let sin spread throughout the feast and make it an awful testimony of Christ’s work to save you. Live your life in sincerity and truth.

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