1 Corinthians 5:6Meaning & Commentary from the Church Fathers

Having stated his decision briefly and without delay, he then again turns to the Corinthians and uses rebuke: “Your boasting is not good,” 1 Cor 5:6. He shows that, by boasting of him, they were the cause of his impenitence until the present time.

Then he explains that he does this for the good not only of the sinner, but of them all: “Do you not know,” he continues, “that a little leaven leavens the whole lump?”

Although the sin, he says, is his, if it is left unattended, it can infect the whole body of the Church. For if the first one who sinned is not delivered to punishment, others will soon fall into the same sin.

By these words he indicates that they should fear and care for the whole Church, and not only for one member. For this reason he uses the image of leaven.

As leaven, he says, though small, changes the whole dough, so this man too, if he remains without rebuke and his sin without punishment, will infect the rest.

“Your boasting is not good.” He hints that they themselves were not allowing the fornicator to come to repentance, for they boasted in him, and he was among their wise men. “Do you not know that a little leaven leavens the whole lump?” I am concerned, he says, for you also, and not for him alone. For if evil is left unnoticed, it can infect the other members of the Church. Leaven, though small in itself, leavens the whole lump and transforms it into itself. So this man’s sin will draw many others after it.

“Put away the evil one from among yourselves” (1 Cor 5:13). The divine Apostle commands this concerning the man condemned for unlawful union, ordering him to be torn away from the common fullness of the Church. Otherwise the “little leaven” of vice in the condemned man, as he says, would make useless the whole mixture of ecclesial prayer.

So too the sin of one man, when report of it is not disputed, defiles many. For all who knew did not turn away, and those who could rebuke pretended not to notice. A man does not perceive his own sin behind him when he is neither rebuked nor avoided by anyone.

By “old leaven” the Apostle means what was in them before baptism. He commands them to cleanse themselves from it and to be “unleavened” loaves, having no remnants of this leaven in themselves. Since he mentioned “unleavened” loaves, which the Jews ate during Passover, he added in sequence: “For Christ, our Passover, has been sacrificed for us.” We too have a Lamb, who took upon Himself what is offered in sacrifice for us.

But what, the Latin will say, does Paul say? He says that unleavened bread must be offered, having in mind these words of the Apostle: “Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth,” 1 Cor 5:8.

O foolishness, we who think rightly will say. Is this how you understand what the herald of God says? O man, he says these words in order to destroy the root and cause of sin.

“Not with the old leaven of malice and wickedness,” he says quite rightly. And you also must reject this leaven: the fornication of those who fornicated in Corinth, and every other impurity. For the whole purpose and the apostolic word concern this.

“To leaven.” The fermentation of the whole mass of dough from a little leaven serves the Apostle as an image to explain the corrupting action of a vicious man upon the whole community. “To leaven” here means “to corrupt.” The Vulgate translated it precisely so: corrumpit.

Therefore the criminal must be treated so strictly, the Apostle of Christ explains, because even one bad example can infect many. “Your boasting is not good,” that is, that apart from this ungodly man all the others are without reproach. “Do you not know that a little leaven leavens the whole lump?”

Having rebuked the manifest adulterer, the Apostle then rebukes others, and generally all who had not abandoned pagan, vicious life. He calls this viciousness the old leaven.

This comparison is very exact. Just as the smallest quantity of leaven makes the whole dough leavened, so a small remnant of pagan sinfulness could corrupt the whole life of the Corinthian Christians.

In contrast to sinful leaven, Christians must present themselves as a new composition, like that made at the feast of the Hebrew Pascha. That feast consisted in eating the pure lamb with unleavened bread.

It was kept in memory of deliverance from Egyptian bondage, and as an image of salvation from sin through Christ, the Lamb slain for the sins of the whole world.

He returns to what was said before: you were boasting of this, and not rather mourning. “Your boasting is not good.” Either there is nothing for which to praise you, since you allowed such a sin in your community and have not yet cared to heal it.

Or else, you did not act well in boasting of such a person. This rooted him more deeply in sin and kept him in blindness and impenitence.

By these words the Apostle “shows that, by boasting of him, they were the cause of his impenitence until the present time. Then he explains that he does this for the good not only of the sinner, but of all of them.