1 Corinthians 5

7. old leaven--The remnant of the "old" ( Ephesians 4:22-24 ) heathenish and natural corruption. The image is taken from the extreme care of the Jews in searching every corner of their houses, and "purging out" every particle of leaven from the time of killing the lamb before the Passover ( Deuteronomy 16:3 Deuteronomy 16:4 ). So Christians are continually to search and purify their hearts ( Psalms 139:23 Psalms 139:24 ).
as ye are unleavened--normally, and as far as your Christian calling is concerned: free from the leaven of sin and death ( 1 Corinthians 6:11 ). Paul often grounds exhortations on the assumption of Christian professors' normal state as realized ( Romans 6:3 Romans 6:4 ) [ALFORD]. Regarding the Corinthian Church as the Passover "unleavened lump" or mass, he entreats them to correspond in fact with this their normal state. "For Christ our Passover ( Exodus 12:5-11 Exodus 12:21-23 , John 1:29 ) has been (English Version, "is") sacrificed for us"; that is, as the Jews began the days of unleavened bread with the slaying of the Passover lamb, so, Christ our Passover having been already slain, let there be no leaven of evil in you who are the "unleavened lump." Doubtless he alludes to the Passover which had been two or three weeks before kept by the Jewish Christians ( 1 Corinthians 16:8 ): the Gentile Christians probably also refraining from leavened bread at the love-feasts. Thus the Jewish Passover naturally gave place to our Christian Easter. The time however, of keeping feast (metaphorical; that is, leading the Christian life of joy in Christ's finished work, compare Proverbs 15:15 ) among us Christians, corresponding to the Jewish Passover, is not limited, as the latter, to one season, but is ALL our time; for the transcendent benefits of the once-for-all completed sacrifice of our Passover Lamb extends to all the time of our lives and of this Christian dispensation; in no part of our time is the leaven of evil to be admitted.
For even--an additional reason, besides that in 1 Corinthians 5:6 , and a more cogent one for purging out every leaven of evil; namely, that Christ has been already sacrificed, whereas the old leaven is yet unremoved, which ought to have been long ago purged out.

8. not . . . old leaven--of our unconverted state as Jews or heathen.
malice--the opposite of "sincerity," which allows no leaven of evil to be mixed up with good ( Matthew 16:6 ).
wickedness--the opposite of "truth," which allows not evil to be mistaken for good. The Greek for "malice" means the evil habit of mind; "wickedness," the outcoming of the same in word and deed. The Greek for "sincerity" expresses literally, a thing which, when examined by the sun's light, is found pure and unadulterated.

9. I wrote . . . in an epistle--rather, "in the Epistle": a former one not now extant. That Paul does not refer to the present letter is proved by the fact that no direction "not to company with fornicators" occurs in the previous part of it; also the words, "in an (or, the) epistle," could not have been added if he meant, "I have just written" ( 2 Corinthians 10:10 ). "His letters" (plural; not applying to merely one) confirm this. 2 Corinthians 7:8 also refers to our first Epistle, just as here a former letter is referred to by the same phrase. Paul probably wrote a former brief reply to inquiries of the Corinthians: our first Epistle, as it enters more fully into the same subject, has superseded the former, which the Holy Spirit did not design for the guidance of the Church in general, and which therefore has not been preserved.

10. Limitation of the prohibition alluded to in 1 Corinthians 5:9 . As in dissolute Corinth to "company with no fornicators," &c. would be almost to company with none in the (unbelieving) world; ye need not utterly ("altogether") forego intercourse with fornicators, &c., of the unbelieving world (compare 1 Corinthians 10:27 , John 17:15 , 1 John 5:18 1 John 5:19 ). As "fornicators" sin against themselves, so "extortioners" against their neighbors, and "idolaters" against God. The attempt to get "out of the world," in violation of God's will that believers should remain in it but keep themselves from its evil, led to monasticism and its consequent evils.

11. But now--"Now" does not express time, but "the case being so," namely, that to avoid fornicators, &c., of the world, you would have to leave the world altogether, which would be absurd. So "now" is used in Hebrews 11:16 . Thus we avoid making the apostle now retract a command which he had before given.
I have written--that is, my meaning in the letter I wrote was "not to keep company," &c.
a brother--contrasted with a "fornicator . . . of the world" ( 1 Corinthians 5:10 ). There is less danger in associating with open worldlings than with carnal professors. Here, as in Ephesians 5:3 Ephesians 5:5 , "covetousness" is joined with "fornication": the common fount of both being "the fierce and ever fiercer longing of the creature, which has turned from God, to fill itself with the inferior objects of sense" [TRENCH, Greek Synonyms of the New Testament]. Hence "idolatry" is associated with them: and the covetous man is termed an "idolater" ( Numbers 25:1 Numbers 25:2 ). The Corinthians did not fall into open idolatry, but ate things offered to idols, so making a compromise with the heathen; just as they connived at fornication. Thus this verse prepares for the precepts in 1 Corinthians 8:4 , &c. Compare the similar case of fornication, combined with a similar idolatrous compromise, after the pattern of Israel with the Midianites ( Revelation 2:14 ).
no not to eat--not to sit at the same table with such; whether at the love-feasts (agapæ) or in private intercourse, much more at the Lord's table: at the last, too often now the guests "are not as children in one family, but like a heterogeneous crowd of strangers in an inn" [BENGEL] (compare Galatians 2:12 , 2 John 1:10:11 ).

12. what have I to do--You might have easily understood that my concern is not with unbelievers outside the Church, but that I referred to those within it.
also--Implying, Those within give me enough to do without those outside.
do not ye, &c.--Ye judge your fellow citizens, not strangers: much more should I [BENGEL]. Rather, Is it not your duty to judge them that are within? God shall judge them that are without: do you look at home [GROTIUS]. God is the Judge of the salvation of the heathen, not we ( Romans 2:12-16 ). Paul here gives an anticipatory censure of their going to law with saints before heathen tribunals, instead of judging such causes among themselves within.

13. put away from among yourselves that wicked--Sentence of excommunication in language taken from Deuteronomy 24:7 .