The Sin of Incest in Scripture and Biblical Law
The sin of incest, broadly understood as sexual relations between close relatives, is addressed in biblical law, particularly within the Mosaic covenant. While the term "sin" itself encompasses any transgression of God's law [1], including acts of unrighteousness [1] and rebellion against God [1], incest is specifically identified as a "shameful sin" (Hebrew: zimmah) [7]. This term is associated with severe sexual crimes such as gang-rape and prostitution in other biblical contexts [7].
The Old Testament provides explicit prohibitions against various forms of incest. Leviticus 18 and 20 detail a range of forbidden sexual relationships, including those with parents, stepparents, siblings, half-siblings, grandchildren, aunts, uncles, and daughters-in-law. These laws establish boundaries for sexual conduct within families, defining what constitutes an unlawful union. For instance, Abraham Ibn Ezra notes that the specific mention of punishment for relations with a sister in Leviticus 20:17 highlights the particular vulnerability of such relationships, given that siblings often grow up together and may be alone [9]. He also suggests that the absence of explicit punishments for relations with a son's or daughter's daughter implies reliance on oral tradition for such cases [9].
The severity of incest is underscored by the penalties prescribed. In some cases, the law states that those who commit incest "shall bear his iniquity" [9], indicating divine judgment. The broader concept of sin is often linked to iniquity, with Psalms 51:5 stating, "Behold, I was born in iniquity. In sin my mother conceived me" [2]. John Gill interprets this verse as referring to original sin and corruption derived through natural generation [8]. The Tyndale House commentary on Psalms 58:3 further elaborates that all human beings are born sinners, with the wicked indulging their sinful nature and the godly fighting against it [3].
The biblical understanding of sin, including incest, is that it is a profound offense against God. Paul, in Romans 1:18-32, emphasizes universal sinfulness, stating that God's anger is a necessary response to sin [6]. The first sin of humanity, as described in Genesis 3:13, involved disobedience and a preference for the creature over the Creator [4]. Deliberate sins are characterized by an insolent or arrogant attitude, with rebellion being considered a "great sin" [5]. Thus, incest, as a violation of God's established order for human relationships, falls under the umbrella of such grievous transgressions.
Sources
- Torrey's Topical Textbook “Torrey's Topical Textbook: Sin — Is the transgression of the law -- 1Jo 3:4. Is of the devil -- 1Jo 3:8; Joh 8:44. All unrighteousness is -- 1Jo 5:17. Omission of what we know to be good is -- Jas 4:17. Whatever is not of faith is -- Ro 14:23. The thought of foolishness is -- Pr 24:9. All the imaginations of the unrenewed heart are -- Ge 6:5; 8:21. Described as Coming from the heart. -- Mt 15:19. The fruit of lust. -- Jas 1:15. The sting of death. -- 1Co 15:56. Rebellion against God. -- De 9:7; Jos 1:18. Works of darkness. -- Eph 5:11. Dead works. -- Heb 6:1; 9:14. The abominable thing that Go”
- Psalms “Behold, I was born in iniquity. In sin my mother conceived me. -- Psalms 51:5”
- Psalms (Protestant academic) “Tyndale House on Psalms 58:3: 58:3 All human beings are born sinners (see 51:5); however, whereas the wicked indulge their sinful nature, the godly fight against it (Rom 7:19-23; Jas 4:1-10).”
- Genesis (Presbyterian) “Jamieson, Fausset & Brown on Genesis 3:13: beguiled--cajoled by flattering lies. This sin of the first pair was heinous and aggravated--it was not simply eating an apple, but a love of self, dishonor to God, ingratitude to a benefactor, disobedience to the best of Masters--a preference of the creature to the Creator.”
- Psalms (Protestant academic) “Tyndale House on Psalms 19:13: 19:13 An individual who commits deliberate sins does so with an insolent (86:14) or arrogant (119:21, 69) attitude. • The great sin is rebellion (see 32:1).”
- Romans (Protestant academic) “Tyndale House on Romans 1:18: 1:18–3:20 Paul delays exploring the theme of righteousness through faith (see 3:21) until after he first teaches about universal sinfulness. Gentiles (1:18-32) and Jews (2:1–3:8) are equally under sin’s power and cannot find favor with God by any action of their own (3:9-20). 1:18 God’s anger is not a spontaneous emotional outburst, but the holy God’s necessary response to sin. The Old Testament often depicts God’s anger (Exod 32:10-12; Num 11:1; Jer 21:3-7) and predicts a decisive outpouring of God’s wrath on human sin at the end of history. While Paul usually de”
- Job (Protestant academic) “Tyndale House on Job 31:11: 31:11 The Hebrew term zimmah (shameful sin) is associated with sexual crimes such as incest (“wicked act,” Lev 18:17), gang-rape (“terrible . . . crime,” Judg 20:6), and prostitution (Ezek 23:49).”
- Psalms (Baptist/Reformed) “John Gill on Psalms 51:5: Behold, I was shapen in iniquity,.... This cannot be understood of any personal iniquity of his immediate parents; since this respects his wonderful formation in the womb, in which both he and they were wholly passive, as the word here used is of that form; and is the amazing work of God himself, so much admired by the psalmist, Psa 139:13; and cannot design any sinfulness then infused into him by his Maker, seeing God cannot be the author of sin; but of original sin and corruption, derived to him by natural generation: and the sense is, that as soon as ever the mass ”
- Sefaria (Jewish (Rationalist)) “Abraham Ibn Ezra on Leviticus 20:17: HE SHALL BEAR HIS INIQUITY. He alone shall bear his iniquity. The reason scripture mentions these things 55 Marriage, consensual intercourse outside of marriage, and rape. It does not mention all three with regard to the other prohibited relations. regarding the sister is that they grew up in one house and are young people who play. The brother is always alone with his sister. Scripture does not mention the punishment for intercourse with the daughter of one’s son or the daughter of one’s daughter, for it relied on the oral Torah. 56 See Sanhedrin 51a. It i”