The Reason for Discipline
Your boasting is not good. Do you not know that a little leaven leavens the whole lump of dough? Clean out the old leaven, that you may be a new lump, just as you are in fact unleavened. For Christ our Passover also has been sacrificed. Let us therefore celebrate the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth. (5:6–8)
Discipline sometimes must be severe because the consequences of not disciplining are much worse. Sin is a spiritual malignancy and it will not long stay isolated. Unless removed it will spread its infection until the whole fellowship of believers is diseased.
The Corinthians could not face that truth, although they had been taught it long before. Their pride caused them to be forgetful and neglectful, and Paul tells them, Your boasting is not good. “Look where your arrogance and your boasting have brought you. Because you still love human wisdom and human recognition and the things of this world, you are completely blinded to the blatant sin that will destroy your church if you don’t remove it.” Do you not know that a little leaven leavens the whole lump of dough? In a more modern figure he was saying, “Don’t you know that one rotten apple can spoil the whole barrel?”
God diagnoses spiritual health only by the standards of His righteousness. We can be highly gifted, highly blessed, highly successful, and highly respected—and also be highly sinful. That was the condition of the Corinthian church. The believers thee had been under the ministry of Paul, Apollos, and Peter. They were “enriched in [Christ], in all speech and all knowledge,” the “testimony concerning Christ was confirmed” in them, and they were “not lacking in any gift” (1:5–7). Yet they were proud, arrogant, boastful, and immoral—even tolerant of sins, including a sin that pagans condemned.
Similarly, the scribes and the Pharisees of Jesus’ day were quite satisfied with themselves. They loved “the place of honor at banquets,” the “respectful greetings in the market place,” and “being called by men, Rabbi” (Matt. 23:6–7). They thought they deserved such recognition. But Jesus pronounced on them a long series of “woes,” in which He pointed out sin after sin of which they were guilty. He characterized them as blind and hypocritical. Their unchecked pride completely blinded them to the most obvious of spiritual principles, and their arrogance caused them to live lives of continuous pretense. “You serpents, you brood of vipers,” Jesus said, “how shall you escape the sentence of hell?” (vv. 13–33). But such pride is less offensive in the case of spiritual hypocrites like the Jews to whom our Lord spoke than it is in the assembly of believers.
A large congregation, an impressive Sunday school, active witnessing and visitation and counseling, and every other sort of good program give no protection or justification to a church that is not faithful in cleansing itself. When sin is willingly, or even neglectfully, allowed to go unchallenged and undisciplined, a larger church will be in danger of a larger malignancy.
In ancient times, when bread was about to be baked, a small piece of dough was pulled off and saved. That little leaven, or yeast, would then be allowed to ferment in water, and would later be kneaded into the next batch of fresh dough to make it rise.
Leaven in Paul’s illustration, as throughout Scripture, represents influence. Usually it refers to the influence of evil, though in Matthew 13:33 it represents the good influence of the kingdom of heaven. In this case, however, evil influence is in view. The whole lump of dough is here the local church. If given opportunity, sin will permeate a whole church just as leaven permeates a whole loaf. Sind’s nature is to ferment, corrupt, and spread.
For the Jews, leaven historically had also represented something bad from the past brought over into the present. When God was preparing Israel to leave Egypt He instructed His people to sprinkle lamb’s blood on their door posts and lintels so that, in the last of the ten plagues on Egypt, the angel of death would pass over and not slay their firstborn (Ex. 12:23). And when they baked bread in preparation for the trek out of Egypt, the Israelites were not allowed to add leaven. For one thing, they did not have time to knead the leaven into the dough and wait for it to rise, since “they could not delay” (v. 39). For another, bread represented sustenance of life, and the Passover and Exodus represented deliverance from the old life (in Egypt) and entrance into the new life (in the Promised Land). The leaven represented the old life—the way of Egypt, the way of the world—which was to be left entirely behind. Consequently, while they were traveling out of Egypt and during every subsequent Passover celebration, the Lord commanded that “nothing leavened shall be seen among you” (13:3, 7). Every bit of leaven was to be thrown out.
Christians likewise are to be separated from the old life. We are to bring none of it into the new life. Clean out the old leaven, that you may be a new lump, just as you are in fact unleavened. For Christ our Passover also has been sacrificed. Clean out is expressed with the use of a compound word (ekkathairō, “to purge or cleanse thoroughly”) to emphasize the completeness of cleansing. As pictured in the Passover in Egypt, the sacrifice of Jesus Christ, God’s perfect Passover Lamb, and the placing of His blood over us, completely separates us from the dominion of sin and the penalty of judgment. We, too, are to remove everything from the old life that would taint and permeate the new As Israel was set free from Egypt as a result of the Passover and was to make a clean break with that oppressor, so the believer is to be totally separated from his old life, with its sinful attitudes, standards, and habits. Christ died to separate us from bondage to sin and give us a new bondage to righteousness (Rom. 6:19), which is the only true freedom.
David Brainerd, who spent his short adult life as a missionary to the American Indians, wrote in his diary:
I never got away from Jesus, and him crucified, and I found that when my people were gripped by this great evangelical doctrine of Christ and him crucified, I had no need to give them instructions about morality. I found that one followed as the sure and inevitable fruit of the other. … I find my Indians begin to put on the garments of holiness and their common life begins to be sanctified even in small matters when they are possessed by the doctrine of Christ and him crucified.
One of the greatest protections from sin that we have as Christians is simply focusing on our Lord and on the sacrifice He made for us. To understand that His death for sin applied to us calls us away from sin and to a clean break with the old ways is to understand the sanctifying work of the cross (see Titus 2:11–14). It is impossible to be occupied with this truth and with sin at the same time.
The conclusion of Paul’s point is that we are to continue to celebrate the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth. The Old Testament Passover was celebrated but once a year, as a reminder of the deliverance from Egypt. The Christian’s celebration should be continuous. Our every thought, every plan, every intention should be under Christ’s control. The perfect unleavened bread FIe desires us to eat is that of sincerity and truth. Sincerity is the attitude of genuine honesty and integrity, from which truth results. In this context, those two words are synonyms for purity, the purity of the cleansed new life in Jesus Christ—which has no place for the leaven, the impurity, of malice and wickedness. Malice speaks of an evil nature or disposition. Wickedness is the act that manifests that evil disposition. We are called to celebrate our Passover in Christ not with an annual feast but with constant life devotion to purity and rejection of sin.
Discipline in the church assists in this celebration by removing impurities that will contaminate and corrupt it. It preserves Christd’s Body from the permeation of evil.
6–7a In 5:2 the report had come to Paul that the Corinthians were “proud” about their toleration of the incestuous man in their midst. Paul picks up on this in v. 6 when he indicates that their “boasting is not good.” In fact, their boasting needs to stop. How so? Paul turns to the metaphor of yeast and the leavening process to explain.
Everyone knows that only a small amount of yeast works its way through the entire batch of dough and makes the dough rise. The majority of references in the NT to this process are negative (see, e.g., Mt 16:5–6; Mk 8:15), showing the permeating power of sin (in the same way we may talk of a rotten apple spoiling the entire barrel). What the Corinthians need to do is to get rid of the leaven (i.e., the rotten apple) in their midst in order to stop the process.
What is that leaven, or yeast? Most interpreters assume that it is the incestuous man. But this is not what the context says. Rather, what is infecting the congregation is their spirit of pride and boasting about their toleration of this man. That is what Paul wants to get rid of among the believers in Corinth. If to accomplish this the sinful man has to be expelled (cf. 5:13), so be it. But Paul does not see the sin of this man’s immorality infecting the congregation, as though that is the rottenness; rather, what is affecting the church is the sin of their pride. If they can get rid of that sin, which is eating its way through the congregation, then they stand a chance of being a “new batch without yeast.”
7b–8 This is, in fact, the reason the Lord Jesus Christ was sacrificed on the cross as our Passover Lamb, in order that we might be reconciled to God (2 Co 5:18–21) and be presented to him as a pure and holy people (see 2 Co 11:2; cf. Php 2:14–16). Paul uses the Passover imagery now because his use of the yeast/leaven metaphor brings to his mind the Feast of the Passover and Unleavened Bread. During this OT feast day, all leaven was to be removed from the houses of the Israelites as a symbol of putting away their sin and impurity in preparation for the killing of the Passover lamb and their remembrance of God’s gracious redemptive event in the exodus.
In a similar manner, the Corinthians are to put away “the yeast of malice and wickedness” (v. 8), namely, their sin of pride and boasting of how tolerant they are in the case of the incestuous man. In its place they are to put the unleavened bread of “sincerity and truth.” “Sincerity” (eilikrineia, GK 1636) is a word that Paul associates with “holiness” in 2 Corinthians 2:12; he associates the cognate adjective eilikrenēs (“unmixed,” “morally pure”) with blamelessness in Philippians 1:10. The only way in which the Corinthians can hope to appear before God in purity and holiness is by getting rid of that pride.
 MacArthur, J. F., Jr. (1984). 1 Corinthians (pp. 127–130). Chicago: Moody Press.
 Verbrugge, V. D. (2008). 1 Corinthians. In T. Longman III &. Garland, David E. (Ed.), The Expositor’s Bible Commentary: Romans–Galatians (Revised Edition) (Vol. 11, pp. 302–303). Grand Rapids, MI: Zondervan.