Paul addresses a shocking case of sexual sin within the Corinthian church. A man is living in an incestuous relationship with his father's wife, yet the church remains arrogant rather than mourning. Paul commands the church to exercise discipline by removing this unrepentant sinner from their fellowship, emphasizing that tolerating such sin corrupts the entire community and contradicts their identity as God's holy people.
Paul opens with the adverb holōs ('actually, altogether'), which can mean either 'universally' or 'actually/really.' The LSB's 'actually' captures Paul's shock that such a report has reached him—this is not rumor but confirmed reality. The present passive akouetai ('it is reported') suggests ongoing reports, perhaps from multiple sources. The double use of porneia in verse 1 creates rhetorical emphasis through repetition, with the second occurrence qualified by the relative clause hētis oude en tois ethnesin ('which not even among the Gentiles'). This comparison would have stung the Corinthians, who prided themselves on their spiritual sophistication. The result clause with hōste plus infinitive (gynaika tina tou patrou echein, 'to have his father's wife') specifies the nature of the immorality: a man is living with his stepmother, a violation of Leviticus 18:8.
Verse 2 pivots with kai to the community's response—or rather, their appalling lack of appropriate response. The perfect periphrastic construction pephysiōmenoi este ('you are puffed up') emphasizes their settled state of arrogance. Paul then employs a sharp contrast: kai ouchi mallon epenthēsate ('and have you not rather mourned?'). The negative ouchi expects a positive answer, making this a rhetorical rebuke. The aorist epenthēsate points to a decisive act of mourning that should have occurred but did not. The purpose clause hina arthē ek mesou hymōn ('so that he might be removed from your midst') uses the passive subjunctive, suggesting that proper mourning should have led to the offender's removal. The phrase ek mesou hymōn ('from your midst') echoes Deuteronomy 17:7 LXX, where the same expression describes purging evil from Israel.
Verses 3-4 form a complex syntactical unit where Paul asserts his apostolic authority to judge despite physical absence. The men...de construction (apōn tō sōmati parōn de tō pneumati) creates a strong contrast between bodily absence and spiritual presence. The perfect kekrika ('I have judged') stands emphatically at the center, indicating that Paul's verdict is already rendered and in force. The participial phrase ton houtōs touto katergazomenon ('the one who has so done this thing') uses the perfect participle to describe the settled state of the offender. Verse 4's syntax is notoriously difficult, with multiple prepositional phrases that can be construed in various ways. The phrase en tō onomati tou kyriou Iēsou ('in the name of the Lord Jesus') likely modifies the infinitive paradounai in verse 5, indicating the authority by which this action is taken. The genitive absolute synachthentōn hymōn ('when you are assembled') sets the scene for corporate action.
Verse 5 delivers Paul's verdict with the aorist infinitive paradounai ('to deliver'), which depends on kekrika in verse 3. The phrase tō Satana ('to Satan') is striking—excommunication means expulsion from the realm of Christ's protection into Satan's domain, the fallen world system. The purpose is twofold, expressed in two eis phrases: eis olethron tēs sarkos ('for destruction of the flesh') and the ultimate goal, hina to pneuma sōthē ('so that the spirit may be saved'). The genitive tēs sarkos is objective—the flesh is what is to be destroyed. The final phrase en tē hēmera tou kyriou ('in the day of the Lord') points to the eschatological horizon: this discipline aims at final salvation at Christ's return. The entire sentence structure reveals Paul's pastoral logic: present severity serves future mercy.
The church that tolerates flagrant sin while congratulating itself on its enlightenment has inverted the gospel. True love mourns what destroys and acts to rescue, even when rescue requires the sharp surgery of exclusion.
The specific sin Paul addresses—a man having 'his father's wife'—directly violates Leviticus 18:8: 'You shall not uncover the nakedness of your father's wife; it is your father's nakedness.' This prohibition appears in the Holiness Code's list of forbidden sexual relations, violations of which defile both individual and community. Leviticus 18:29 prescribes that those who commit such abominations 'shall be cut off from among their people,' using the Hebrew כָּרַת (karat), which the LXX renders with ἐξολεθρεύω (exolethreuo, 'to destroy utterly'). Paul's language of removal 'from your midst' (ek mesou hymōn) echoes the Deuteronomic formula for purging evil from Israel (Deut 17:7, 12; 22:21-22), where the community must actively remove the offender to maintain covenant holiness.
The connection runs deeper than mere legal parallel. In Deuteronomy 22:21, when a woman is found not to be a virgin at marriage, she is to be stoned 'so you shall purge the evil from your midst' (וּבִעַרְתָּ הָרָע מִקִּרְבֶּךָ, ubi'arta hara' miqqirbeka). The LXX translates this as ἐξαρεῖς τὸν πονηρὸν ἐξ ὑμῶν αὐτῶν (exareis ton ponēron ex hymōn autōn), using the same verb αἴρω (airo) that Paul employs in 1 Corinthians 5:2. Paul will quote this formula explicitly in 5:13, showing that he understands church discipline as the New Covenant equivalent of Israel's covenant maintenance. The church, as the new Israel, must guard its holiness not through capital punishment but through excommunication—a 'cutting off' that is social and spiritual rather than physical, yet no less serious in its implications for covenant membership.
Paul shifts from direct confrontation to proverbial wisdom, introducing his argument with the dismissive 'Your boasting is not good' (Οὐ καλὸν τὸ καύχημα ὑμῶν). The rhetorical question that follows—'Do you not know that a little leaven leavens the whole lump?'—assumes shared knowledge of a common principle. The structure οὐκ οἴδατε ὅτι ('do you not know that') appears frequently in 1 Corinthians (3:16; 5:6; 6:2, 3, 9, 15, 16, 19; 9:13, 24) and functions to remind the Corinthians of truths they should already grasp but are failing to apply. The proverb itself uses the present tense ζυμοῖ ('leavens') to indicate a timeless, repeatable truth: leaven always permeates dough. The adjectives μικρά ('little') and ὅλον ('whole') stand in stark contrast, emphasizing the disproportionate effect of a small corrupting influence.
Verse 7 contains the passage's central imperative: ἐκκαθάρατε τὴν παλαιὰν ζύμην ('clean out the old leaven'). The aorist tense demands immediate, decisive action. The purpose clause ἵνα ἦτε νέον φύραμα ('so that you may be a new lump') articulates the goal: the community must actualize in practice what is already true in principle. Paul then grounds this imperative in an indicative: καθώς ἐστε ἄζυμοι ('just as you are in fact unleavened'). The καθώς ('just as') establishes correspondence between identity and action—they must become what they already are. The explanatory γάρ ('for') introduces the theological foundation: καὶ γὰρ τὸ πάσχα ἡμῶν ἐτύθη Χριστός ('For Christ our Passover also has been sacrificed'). The aorist passive ἐτύθη indicates a completed sacrificial act, and the word order places Χριστός in the emphatic final position. This is not mere analogy but typological fulfillment—Christ is the reality to which the Passover lamb pointed.
Verse 8 draws the practical conclusion with ὥστε ('therefore'), moving from indicative to hortatory subjunctive: ἑορτάζωμεν ('let us celebrate the feast'). The present tense transforms Christian existence into a continuous Passover celebration, not a single annual observance. Paul structures the exhortation with a negative-positive contrast: μὴ ἐν ζύμῃ παλαιᾷ μηδὲ ἐν ζύμῃ κακίας καὶ πονηρίας ('not with old leaven, nor with the leaven of malice and wickedness') versus ἀλλ' ἐν ἀζύμοις εἰλικρινείας καὶ ἀληθείας ('but with the unleavened bread of sincerity and truth'). The repetition of ἐν ('with, in') creates a rhythmic parallelism, while the shift from singular ζύμῃ ('leaven') to plural ἀζύμοις ('unleavened things') may suggest the comprehensive nature of Christian virtue. The genitives εἰλικρινείας καὶ ἀληθείας function appositionally—sincerity and truth are not ingredients added to unleavened bread but constitute the unleavened character itself. Paul has thus moved from metaphor (leaven/dough) to typology (Passover) to ethical application (sincerity/truth), creating a tightly woven argument that grounds church discipline in the gospel itself.
Tolerating sin is not compassion but complicity; it betrays both the sinner and the community by allowing corruption to spread unchecked through the body that Christ's sacrifice has already made holy.
Paul opens verse 9 with a reference to a previous letter (now lost to us), clarifying a misunderstanding about his instruction not to associate with sexually immoral people. The epistolary aorist egrapsa ('I wrote') functions as a present from the readers' perspective, though it may also refer to an actual earlier correspondence. The infinitive synanamignysthai ('to associate with') is articular (ἐν τῇ ἐπιστολῇ μὴ συναναμίγνυσθαι), making it the content of what he wrote. The present tense of the infinitive suggests habitual association, not merely incidental contact. Paul's rhetorical strategy here is corrective: he is not backtracking but refining, addressing a misapplication of his earlier instruction.
Verse 10 introduces a strong negation (ou pantōs, 'not at all') that rules out the absurd interpretation that believers should have no contact whatsoever with immoral unbelievers. The catalog of vices—sexually immoral, greedy, swindlers, idolaters—describes the moral landscape of Corinth itself, a city notorious for its commercial opportunism and sexual license. Paul's logic is both practical and theological: complete separation from unbelievers would require leaving the world (ek tou kosmou exelthein), which is neither possible nor desirable for those called to be salt and light. The epei clause ('for then') introduces the reductio ad absurdum: such an interpretation would nullify the church's mission in the world.
The contrast in verse 11 is emphatic: nyn de ('but now') marks the shift from what Paul did not mean to what he does mean. The repetition of egrapsa and mē synanamignysthai creates a deliberate echo of verse 9, but now with a crucial qualifier: ean tis adelphos onomazomenos ('if anyone being called a brother'). The participle onomazomenos is devastating—it suggests nominal Christianity, a claim to brotherhood that behavior contradicts. The expanded vice list now includes revilers and drunkards alongside the earlier categories, and the prohibition extends even to eating with such a person (mēde synesthiein). This is not mere social distancing but a withdrawal of fellowship that communicates the gravity of unrepentant sin and the hope of restoration through shame and exclusion.
Verses 12-13 ground the distinction in jurisdictional terms. Paul's rhetorical questions (ti gar moi, 'for what to me...?'; ouchi, 'is it not...?') expect affirmative answers: he has no business judging outsiders, and the Corinthians do have responsibility to judge insiders. The spatial metaphors exō and esō ('outside' and 'inside') create clear boundaries of accountability. God judges those outside; the church judges those inside. The final command, exarate ton ponēron ex hymōn autōn ('remove the evil person from among yourselves'), is a direct quotation formula from Deuteronomy's instructions for purging evil from Israel. Paul applies covenant holiness language to the church, making explicit that the new covenant community must maintain moral boundaries just as Israel did, not for ethnic purity but for the integrity of witness to the holy God revealed in Christ.
The church's mission in the world requires presence among sinners; the church's integrity as the body of Christ requires separation from those who claim his name while trampling his holiness. We are called to be in the world but not of it—and to ensure that those who are of the world are not falsely in the church.
The LSB's rendering of pornois as 'sexually immoral people' (verses 9-11) maintains clarity while avoiding the archaic 'fornicators' and the overly broad 'immoral people' that might obscure the specifically sexual nature of the sin. The term encompasses all sexual activity outside the covenant of marriage, and the LSB's choice preserves this specificity without resorting to euphemism.
In verse 11, the LSB translates adelphos onomazomenos as 'so-called brother,' capturing the irony and judgment implicit in the participle. The person claims the name without the reality, and the LSB's rendering makes this hypocrisy explicit. This is preferable to translations that soften the phrase to 'anyone who bears the name of brother,' which might miss Paul's pointed critique of nominal Christianity.
The command in verse 13, 'Remove the evil person from among yourselves,' preserves the singular ton ponēron ('the evil one') rather than pluralizing to 'evil persons.' This maintains the echo of the Deuteronomic formula and focuses attention on the specific case at hand—the incestuous man of chapter 5—while establishing a principle applicable to all similar cases. The LSB's choice honors both the immediate context and the Old Testament background.