Leviticus 18:9 · Bible study
Leviticus 18:9 Commentary: Half-Sister Prohibition and 'Born at Home or Abroad'
Hebrew · 6 what the commentators say
Meaning in one sentence
Examine the prohibition of incest with a half-sister, the meaning of 'born at home or abroad', and the cultural context of Leviticus 18:9.
Research Summary
- Meaning: Prohibits sexual relations with a half-sister (or any sister) regardless of her parentage or upbringing.
- Key words: "nakedness" (euphemism for incestuous intercourse), "sister" (includes half-sisters), "born at home or born abroad" (clarifies scope).
- Main debate: Does "born at home or abroad" refer to legitimate vs illegitimate birth, or to a half-sister from a previous marriage?
- Theological theme: God’s holiness requires purity in the most intimate family relationships.
- Best use: Foundation for Christian sexual ethics; text for understanding God’s design for family boundaries.
Translation Comparison
BSB Berean Standard Bible 2020
You must not have sexual relations with your sister, either your father’s daughter or your mother’s daughter, whether she was born in the same home or elsewhere.
WEB World English Bible 2000
“‘You shall not uncover the nakedness of your sister, the daughter of your father, or the daughter of your mother, whether born at home or born abroad.
KJV King James Version 1769
The nakedness of thy sister, the daughter of thy father, or daughter of thy mother, whether she be born at home, or born abroad, even their nakedness thou shalt not uncover.
ASV American Standard Version 1901
The nakedness of thy sister, the daughter of thy father, or the daughter of thy mother, whether born at home, or born abroad, even their nakedness thou shalt not uncover.
YLT Young's Literal Translation 1898
`The nakedness of thy sister, daughter of thy father, or daughter of thy mother, born at home or born without; thou dost not uncover their nakedness.
Darby Darby Bible 1890
The nakedness of thy sister, the daughter of thy father, or daughter of thy mother, born at home, or born abroad — their nakedness shalt thou not uncover.
Douay-Rheims Douay-Rheims Bible 1899
Thou shalt not uncover the nakedness of thy sister by father or by mother: whether born at home or abroad.
Translations in other languages (10 available)
La desnudez de tu hermana, hija de tu padre, ó hija de tu madre, nacida en casa ó nacida fuera, su desnudez no descubrirás.
A nudez de tua irmã, filha de teu pai, ou filha de tua mãe, nascida em casa ou nascida fora, sua nudez não descobrirás.
Tu ne découvriras point la nudité de ta sœur, fille de ton père ou fille de ta mère, née dans la maison ou née hors de la maison.
Du sollst deiner Schwester Blöße, die deines Vaters oder deiner Mutter Tochter ist, daheim oder draußen geboren, nicht aufdecken.
De schaamte uwer zuster, der dochter uws vaders, of der dochter uwer moeder, te huis geboren of buiten geboren, haar schaamte zult gij niet ontdekken.
Non scoprirai la nudità della tua sorella, figliuola di tuo padre o figliuola di tua madre, sia essa nata in casa o nata fuori.
Sromoty siostry twej, córki ojca twego, także córki matki twojej, tak rodzonej, jako i przyrodniej, nie odkryjesz sromoty ich.
Наготы сестры твоей, дочери отца твоего или дочери матери твоей, родившейся в доме или вне дома, не открывай наготы их.
你的姊妹，不拘是異母同父 的，是 異父同母 的，無論 是生 在家 生 在外的，都不可 露 她們的下體。
You may not take your sister, the daughter of your father or of your mother, wherever her birth took place, among you or in another country.
Verse in Context
Original Language (Biblical Hebrew)
Old Testament · Biblical Hebrew · Leviticus 18:9
Source: STEPBible TAGNT/TEHB (CC-BY 4.0). Click or tap a morphology code to see the full parsing.
Scholars' Consensus
Commentators agree that Leviticus 18:9 prohibits sexual relations with a half-sister, whether she shares only a father or only a mother. Keil and Delitzsch specify that the sister in view is a step- or half-sister, not a full sister (though full sisters would be doubly covered). The phrase 'whether born at home or born abroad' is debated. Gill records the interpretation of Aben Ezra and the Targum that it distinguishes legitimate from illegitimate birth, a sister born within marriage or outside it. Keil and Delitzsch follow Lud. de Dieu, taking it to refer to the half-sister from a first marriage: the father's daughter by a deceased wife, or the mother's daughter by a deceased husband. Barnes notes that incest with a sister was 'the distinguishing offence of the Egyptians.' All agree that the verse forbids any sexual relationship with a sister, establishing a boundary that safeguards family integrity and holiness.
How settled is the interpretation?
Interpretive difficulty: Medium
Main views:
- Half-sister from a prior marriage: Keil and Delitzsch cite the phrase 'born at home or born abroad' to indicate a half-sister from a deceased spouse; the wording parallels Lud. de Dieu's interpretation.
- Legitimate vs. illegitimate birth: Gill mentions Aben Ezra and the Targum, interpreting 'born at home' as within lawful marriage and 'born abroad' as born outside it.
- Simple clarification of any half-sister: Some modern readings take the phrase as a redundant legal amplification, ensuring no half-sister is excluded regardless of living situation.
What is clear: The verse prohibits sexual relations with a half-sister, whether she shares only father or only mother.
What Scholars Agree and Debate
| Topic | Agreed | Debated |
|---|---|---|
| Type of sister prohibited | The verse includes half-sisters (same father or same mother). | Some argue the phrase 'sister' normally implies a full sister, but the explicit mention of father or mother shows half-sisters are in view. Others hold that full sisters are implicitly included as well, since they are both father's and mother's daughter. |
| Meaning of 'born at home or born abroad' | It expands the scope so no half-sister is exempt. | Keil and Delitzsch argue it refers to a half-sister from a first marriage (living in the household or elsewhere). Gill records a view that it means legitimate vs. illegitimate birth. The Hebrew can support both readings. |
| Application under the New Covenant | The moral principle against incest remains binding for Christians. | Some Christians see the specific prohibition as part of the civil law of Israel and no longer directly applicable, while others view it as rooted in creation order and perpetually binding. |
| Penalty for violation | Leviticus 20:17 calls it a 'shameful thing' and threatens being 'cut off from the people.' | Interpreters disagree on whether 'cut off' means excommunication, premature death, or being childless. The exact form of punishment is not specified in v.9 itself. |
Historical & Cultural Context
Leviticus 18 stands at the heart of the Holiness Code (chapters 17, 26), where God calls Israel to be distinct from the surrounding nations. The chapter opens with a command not to follow the practices of Egypt or Canaan (v.3), and closes with warnings that the land itself will vomit out those who defile it (v.28). Verse 9 appears within a dense list of prohibitions against incest, each opened by the euphemistic phrase 'uncover their nakedness.'
Gill cites concrete examples: the Egyptians ‘did in imitation of Isis and Osiris’ marry sisters, and the Persians followed the example of Cambyses. Such incestuous unions were known in the ancient Near East, particularly in royal or cultic contexts. Israel's law rejects these practices outright. The surrounding Canaanite nations, according to the text, defiled themselves with these very acts, and God was driving them out (v.24-25).
The phrase 'born at home or born abroad' addresses a practical question in an ancient household: a man's half-sister might be the daughter of his father by a previous wife (raised in the same house) or the daughter of his mother by a previous husband (raised elsewhere). The law closes every loophole. There is no circumstance under which a half-sister is permitted.
The prohibition also echoes the earlier Genesis narratives, where Abraham married his half-sister Sarah (Gen 20:12). By the time of Moses, what once was tolerated is now forbidden, a pattern of progressive revelation in moral law.
Textual Notes
The supplied sources note no significant textual variants for Leviticus 18:9. The Hebrew text is stable across manuscripts. The phrasing 'born at home or born abroad' appears without variation in the major traditions.
Reception History
In Jewish tradition, Leviticus 18:9 was understood as a prohibition against marrying a half-sister, and the Mishnah (Keritot 1:1) includes it among the acts that incur divine punishment if done defiantly. The Targum Onkelos paraphrases 'born at home or born abroad' as distinguishing legitimate and illegitimate daughters, reflecting an early Jewish interpretive tradition. Early Christian writers, such as Augustine in City of God, cited this law as evidence that sexual relations between siblings violate natural law. Medieval theologian Thomas Aquinas treated it under the virtue of chastity, arguing it protects familial bonds. Reformed commentators like Matthew Henry stressed the universal moral principle behind the command. In modern ethics, the verse is often used to argue against all incestuous relationships, though its precise application beyond the immediate sibling relationship is debated.
Preaching This Verse
Three-point outline
- God sets boundaries for sexual intimacy. The prohibition of incest with a half-sister (or any sister) is part of a broader design for family relationships. These boundaries protect family stability and honor.
- Holiness means being different from the world. Leviticus 18 repeatedly contrasts Israel with Egypt and Canaan. What was culturally acceptable elsewhere was forbidden for God’s people. The call to holiness still shapes Christian ethics today.
- God cares for the vulnerable. A half-sister, especially one born outside the home, might be seen as more accessible or unprotected. God’s law places a protective wall around her.
Five-point outline
- The prohibition includes half-sisters by either parent.
- “Born at home or abroad” extends the ban to every case, whether the sister lived in the household or elsewhere.
- This law distinguishes Israel from the incestuous practices of surrounding nations.
- It reaffirms the created order of family distinct from sexual union.
- It points to Christ, who creates one new family where purity and love replace exploitation.
Illustration hooks
- Blended families today: When a parent remarries, new step-siblings enter the picture. This verse raises the question of boundaries in modern blended households, even though the legal setting differs.
- Historical marriages among royalty: Egyptian pharaohs often married their sisters to keep the bloodline pure. This law shows that God’s people are a different kind of kingdom.
- A family trust: Families have boundaries that protect trust. Violating that trust within the family causes deep, lasting harm, something God’s law anticipates.
Questions your congregation is asking
- Does this mean it's wrong to marry a cousin? (The text does not explicitly address cousins; later Jewish and Christian traditions have extended the principle.)
- Why did Abraham marry his half-sister if it's forbidden here?
- How does this law apply to Christians today, since we are not under the Mosaic Law?
Leading a Discussion
This small group guide focuses on Leviticus 18:9 within its context of God's call to holiness. Read the verse aloud along with the surrounding verses (18:6, 18). Discuss what the law reveals about God's character and his design for family relationships.
Discussion questions
- What does the phrase “uncover the nakedness of your sister” mean in this context? How does the Bible use euphemism to speak about sexual matters?
- The verse specifies both father’s daughter and mother’s daughter. Why might the law need to name both?
- What does “born at home or born abroad” add to the prohibition? What situations might it have covered?
- How does Leviticus 18:9 help us understand God’s view of family? Why are sexual boundaries within the family so important?
- Look at Leviticus 20:17. What does the penalty “cut off” suggest about the seriousness of this sin?
- Some ancient cultures (Egypt, Persia) permitted brother-sister marriage. How does this law distinguish Israel from those cultures?
- Christians disagree on how the Old Testament ceremonial and civil laws apply today. In what sense does this particular prohibition still speak to us?
Word Study
The key original-language words in this verse. Select any word for its full lexicon entry — meaning, every occurrence in Scripture, and related words.
Cross-References
Source: Treasury of Scripture Knowledge (TSK, public domain)
| Leviticus 18:11 | “‘You shall not uncover the nakedness of your father’s wife’s daughter, conceived by your father, since she is your sister. |
| Leviticus 20:17 | “‘If a man takes his sister—his father’s daughter, or his mother’s daughter—and sees her nakedness, and she sees his nakedness, it is a shameful thing. They shall be cut off in the sight of the children of their people. He has uncovered his sister’s nakedness. He shall bear his iniquity. |
| Deuteronomy 27:22 | ‘Cursed is he who lies with his sister, his father’s daughter or his mother’s daughter.’ All the people shall say, ‘Amen.’ |
| II Samuel 13:11 | When she had brought them near to him to eat, he took hold of her and said to her, “Come, lie with me, my sister!” |
| II Samuel 13:14 | However, he would not listen to her voice; but being stronger than she, he forced her and lay with her. |
| Ezekiel 22:11 | One has committed abomination with his neighbor’s wife, and another has lewdly defiled his daughter-in-law. Another in you has humbled his sister, his father’s daughter. |
Interlinear and lexical data from STEPBible (CC BY 4.0). Cross-reference data from OpenBible.info (CC BY 4.0). Commentaries are public domain.
For personal reflection
Read the devotional page — prayer, application, and "for families"
What the Commentators Say
5 public-domain commentaries, condensed into plain language.
Barnes' Notes on the Bible Protestant 1832
Barnes explains that the phrase "thy sister" points to a sin especially characteristic of the Egyptians. He treats this as a distinctive national offense, singling out a specific cultural failing.
Geneva Bible Notes Reformed 1599
The Geneva note stresses that this prohibition covers every kind of sister: a full sister, a half-sister by either parent, and even one born outside the household. No degree of relationship or circumstance permits uncovering her shame.
Gill's Exposition of the Bible Baptist 1748
Gill explains that marrying or having relations with a sister was necessary for humanity's early growth, as Adam's children had no one else. But once population increased, it became unlawful. He specifies that this applies whether the sister is from the father or mother, and whether born in lawful marriage or not.
Keil & Delitzsch OT Commentary Protestant 1876
Keil-Delitzsch restricts "sister" in this command to a half-sister, one who shares only a father or a mother. They explain that the phrase about birth at home or abroad clarifies which parent the half-sister descends from, not her legitimacy. They also note that in Leviticus 20:17, the Hebrew word for such an act is the same one usually meaning lovingkindness, but there it signifies dishonor and shame.
Matthew Henry's Commentary Reformed/Presbyterian 1710
Henry emphasizes that these prohibitions rest on God's own authority and the natural bonds of family. He stresses that approaching near kin violates the honor due to parents and corrupts the sacred order of relationships, making such acts not merely unclean but wicked.