In 1 Corinthians 5:1-2 more leaven is mentioned: "It is reported commonly that there is fornication among you, and such fornication as is not so much as named among the Gentiles, that one should have his father's wife. And ye are puffed up, and have not rather mourned, that he that hath done this deed might be taken away from among you." Then verses 6-8: "Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? 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: 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."
Verses 11-13 continue: "But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such a one, no, not to eat. For what have I to do to judge them also that are without? do not ye judge them that are within? But them that are without God judgeth. Therefore put away from among yourselves that wicked person." We must realize that the Lord will never allow this kind of wicked person to stay in the church life. They must be put away. In a sense they must be chased away, even excommunicated. Thus, we can see there are two kinds of persons with whom we should not fellowship. First are the antichrists like those mentioned in 2 John, who have gone forward and do not abide in the teaching of Christ. The antichrists do not believe that Christ is God or that Christ is the Son of God. They do not believe that Christ died on the cross to accomplish redemption, was resurrected, and today is enthroned in the heavens. These are the antichrists. We should not greet them, and we should not grant them hospitality. The second are the wicked persons who are mentioned in 1 Corinthians. We should not allow them to remain among us unless they repent because it is an insult to the testimony of God. If we allow such wicked persons to remain in the church life, it will become dirty, polluted, and insulted, and we will lose the testimony of God. We must be alert not to receive any antichrists and not to allow any wicked persons to remain among us. The church must be clear of all these dark things.
We can see the seed of leaven developed also in Galatians 1:6-9: "I marvel that you are so quickly removing from Him Who has called you in the grace of Christ to a different gospel, which is not another; only there are some who trouble you and desire to pervert the gospel of Christ. But if even we or an angel out of heaven should preach to you a gospel besides that which we have preached to you, let him be accursed. As we have said before, now also I say again, If anyone preaches to you a gospel besides that which you have received, let him be accursed." Surely that kind of gospel which was besides the gospel that Paul preached is a kind of leaven.