Deuteronomy 27:23 Commentary: Curse on Incest with Mother-in-Law

Deuteronomy 27 describes a dramatic covenant-renewal ceremony at Shechem, between Mount Gerizim and Mount Ebal. After crossing the Jordan, the tribes were to split: six on Gerizim to pronounce blessings, six on Ebal to stand under the curses. The Levites, not as priests but as representatives of all Israel, “shall speak and say unto all the men of Israel with a loud voice” (v. 14), reciting twelve specific evils. Each curse addresses a sin that could be hidden: setting up an idol in secret, moving a landmark, misleading the blind, striking a neighbor secretly. Sexual violations fit this pattern perfectly.

In the ancient Near East, marriage alliances often created complex family bonds, and the law drew sharp lines to prevent the confusion of kinship roles. Leviticus 18:17 forbids uncovering the nakedness of “a woman and her daughter”; 20:14 calls taking both a wife and her mother “wickedness” and prescribes burning. Ellicott’s commentary (though not directly on this verse) notes that in some Persian and Eastern cultures such unions were tolerated; Israel was to be different. The public recitation made every listener a witness and a guarantor. Each curse ends with “and all the people shall say, Amen.” The Hebrew verb amar (say) is in the imperfect, suggesting a repeated, solemn declaration. The word amen (H0543, “truly, so be it”) bound the whole congregation to God’s judgment, transforming passive hearing into active consent. By answering “Amen,” every person, young, old, rich, poor, took responsibility for upholding the law in community life. This ceremony did not merely inform; it forged a nation under covenant, where private acts could not escape public accountability before God.

The consulted commentaries and resources note no significant textual variants for Deuteronomy 27:23. The Hebrew text is stable across the Masoretic tradition and ancient versions. The translations differ only in English idiom (“lieth with” vs. “sleeps with”), all conveying the same sense. No early manuscript disagreement is reported for this verse.

In Jewish tradition, Deuteronomy 27:23 formed part of the covenantal liturgy at Shechem, rehearsed as a perpetual reminder of the community’s boundaries. The rabbis included this prohibition in discussions of forbidden marriages (e.g., m. Yevamot). Christian interpreters have consistently read the verse as reinforcing the moral law against incest, often linking it to Paul’s treatment of sexual immorality in 1 Corinthians 5. Reformers such as Calvin and Luther, in their commentaries on Deuteronomy, treated the twelve curses as a serious call to national and personal holiness. The “Amen” response has been cited in writings on congregational worship as a model of corporate confession and assent to God’s Word. Today, the verse is used in studies on family ethics, covenant theology, and the public dimension of faith.

Three-point outline

1. The specificity of the curse. This is not a general warning; it names a particular relationship. The law protects the mother-in-law as a member of the extended family, preventing sexual exploitation that would corrupt the marriage bond. God cares about the details of family integrity.
2. The publicity of the response. Every person says “Amen.” This is not a private prayer but a national declaration. The community agrees with God’s judgment, affirming that some acts are never acceptable, no matter how hidden.
3. The gospel shadow. Christ became a curse for us (Galatians 3:13). The curses we deserve, for our secret sins and family disorders, were carried to the cross. The “Amen” of judgment becomes an “Amen” of salvation for those in Christ.

Five-point outline

1. The covenant context: This curse is part of Israel’s formal agreement with God at Shechem.
2. The forbidden act: Incest with a mother-in-law is identified as a violation of the created order.
3. The hidden nature: The curse targets sins likely to be done in secret.
4. The community’s role: The people’s “Amen” makes them morally complicit or obedient.
5. The warning for today: Family boundaries still matter; God sees what is hidden, and the church is called to speak truth.

Illustration hooks

• The feeling of a courtroom when the judge pronounces a sentence and the bailiff says “All rise”, a solemn moment that everyone participates in.
• A family where one member is harming another, and the rest refuse to speak up. The “Amen” is the opposite: a public “we will not tolerate this.”
• A wedding vow: two people say “I do” before witnesses. In Deuteronomy, the whole nation says “We do” to God’s standards.

Questions your congregation is asking

• Why is the mother-in-law singled out? Are there other similar sins not listed?
• Does this mean the church should publicly pronounce curses today?
• What does “Amen” mean in this context, and how does it affect my worship when I say it at church?

Deuteronomy 27:23 stands as one of twelve public curses recited at Mount Ebal. The people’s unified “Amen” echoes far beyond the ceremony: it models the kind of accountability that ought to mark God’s people. This session invites small groups to explore why a seemingly specific prohibition carries such weight and how corporate affirmation shapes faithful community life.

Discussion questions

1. What is the scenario that this curse prohibits? Why do you think it is included in the same list as idolatry, murder, and moving a landmark?
2. Look at the surrounding verses (vv. 20, 22). What pattern do you notice about the kinds of sexual sin listed? How does verse 23 fit that pattern?
3. Read Leviticus 18:17 and 20:14. How do these cross-references deepen your understanding of why this act is called “wickedness”?
4. The people were not just silent observers; they had to speak “Amen.” What does that response say about corporate responsibility? How can a church community today practice similar accountability without becoming legalistic?
5. Some sins are done in secret. This curse is pronounced out loud for all to hear. What does that say about God’s attitude toward hidden sin?
6. How does the gospel address the curse we deserve? In what ways does Jesus’ death transform our “Amen” from one of judgment to one of faith?
7. In your own life, where is God calling you to say “Amen” to His standards, even when it costs you something?