Deuteronomy 25:5 not only permits but commands a man to marry his deceased brother's childless widow — the institution of levirate marriage (Hebrew yibbum), with the explicit purpose of raising up offspring to perpetuate the dead brother's name. Leviticus 20:21 flatly prohibits exactly the same act, calling it an "unclean thing" (niddah) that uncovers the brother's nakedness, with the penalty that the couple shall be childless. Same action, opposite rulings.
Proposed answers
People have answered this in several ways; GEBible presents them as equal peers.
A man may marry his brother's widow
If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not marry without unto a stranger: her husband's brother shall go in unto her, and take her to him to wife, and perform the duty of an husband's brother unto her.
5If brothers dwell together, and one of them dies and has no son, the wife of the dead shall not be married outside to a stranger. Her husband’s brother shall go in to her, and take her as his wife, and perform the duty of a husband’s brother to her.
What follows is one scholar’s way of reading this disagreement— a critical-historical view that often concludes the texts genuinely disagree. It draws on the peer-reviewed sources listed below and stands as one position among the answers above, presented for transparency, not as GEBible’s position.
How critical scholarship weighs this: Widely regarded as a genuine contradiction
This summarizes where critical scholarship tends to land on this tension — a report on the field’s center of gravity, not GEBible’s own ruling.
Deuteronomy 25:5-10 commands levirate marriage (Hebrew yibbum): when brothers dwell together and one dies childless, the surviving brother "shall go in unto her, and take her to him to wife," so that the firstborn "shall succeed in the name of his brother which is dead, that his name be not put out of Israel." Leviticus 20:21 declares the seemingly identical act forbidden: "if a man shall take his brother's wife, it is an unclean thing (niddah); he hath uncovered his brother's nakedness; they shall be childless." The Hebrew niddah ordinarily denotes menstrual impurity and by extension abhorrent defilement, and the prescribed consequence — childlessness ("riyriym, 'stripped/childless') — is thematically barbed: it is the precise outcome the Deuteronomic levirate exists to prevent.
The most natural source-critical placement is that Leviticus 20:21 belongs to the Holiness Code (H, Lev 17-26), whose incest catalogue in Leviticus 18 prohibits "uncovering the nakedness" of a long list of kin defined through a male relative — father's wife, daughter-in-law, and at 18:16 "thy brother's wife." H's logic is genealogical and cultic: such unions defile the land. Deuteronomy 25 (D) operates from a different concern — the preservation of the dead man's name, line, and property within the patrimony. Two legal traditions, two priorities, one act.
The strongest harmonization, defended by Archer and by John Walton, restricts the Levitical prohibition to a brother's wife while the brother is alive, making it a prohibition of adultery and incest within a living union, and reserves Deuteronomy 25 for the widow of a brother who has died childless. This reading has real support: Leviticus 18:16's parallel sits in a list otherwise concerned with relations that would constitute adultery or rivalry within the extended household, and Jacob Milgrom argues that 18:16 indeed contemplates the wife of a living brother. The reading thus resolves the parallel at 18:16 cleanly. The difficulty is that Leviticus 20:21 itself does not specify the brother's state, and its penalty clause (childlessness) is most pointed precisely if the union in view is one undertaken after a brother's death to produce children — which is exactly the levirate situation. If H simply meant adultery with a living brother's wife, the death penalty applied elsewhere in the chapter to adultery (Lev 20:10) would be expected, not the distinctive sentence of childlessness.
The rabbinic tradition itself conceded a real conflict and resolved it by legislative arbitration rather than by claiming the laws never overlapped. The Mishnah's entire tractate Yebamot is devoted to defining when the Deuteronomic levirate obligation overrides the general Levitical prohibition of a brother's wife, concluding that the mitzvah of yibbum suspends the prohibition only in the precise case of a childless widow, and that outside that case the prohibition stands with full force. That is not the harmony of two laws that never touched; it is a ruling about which of two genuinely competing statutes prevails in a defined situation. The narrative tradition assumes levirate duty as normative and praiseworthy — Genesis 38 (Tamar, Judah, and the failure of Onan) and the book of Ruth both turn on the obligation to raise up seed for a dead kinsman.
Where the critical reading lands: a real legal tension between H and D that the case-distinction harmonization can partly but not fully dissolve; the rabbis themselves treated it as a conflict requiring one law to override the other.
Sources for this reading
Jacob Milgrom, Leviticus 17-22 (AB 3A; Doubleday, 2000) pp. 1543-1546on Leviticus 18:16 and 20:21Leviticus 18:16, Leviticus 20:21
Jeffrey H. Tigay, Deuteronomy (JPS Torah Commentary; Jewish Publication Society, 1996) pp. 231-234on Deuteronomy 25:5Deuteronomy 25:5
Raymond Westbrook, "The Law of the Biblical Levirate," Revue Internationale des Droits de l'Antiquité 24 (1977) pp. 65-87on Deuteronomy 25:5 and Leviticus 20:21Deuteronomy 25:5, Leviticus 20:21
Eryl W. Davies, "Inheritance Rights and the Hebrew Levirate Marriage," Vetus Testamentum 31 (1981) pp. 138-144 and 257-268on Deuteronomy 25:5Deuteronomy 25:5
Israel Knohl, The Sanctuary of Silence: The Priestly Torah and the Holiness School (Fortress, 1995) pp. 102-110on Leviticus 20:21Leviticus 20:21
Gleason L. Archer, Encyclopedia of Bible Difficulties (Zondervan, 1982) pp. 137-138on Deuteronomy 25:5 and Leviticus 20:21Deuteronomy 25:5, Leviticus 20:21
Examining the tension
What follows is one scholar’s way of reading this disagreement — a critical-historical view that often concludes the texts genuinely disagree. It draws on the peer-reviewed sources listed below and stands as one position among the answers above, presented for transparency, not as GEBible’s position.
How critical scholarship weighs this: Widely regarded as a genuine contradiction
This summarizes where critical scholarship tends to land on this tension — a report on the field’s center of gravity, not GEBible’s own ruling.
Deuteronomy 25:5-10 commands levirate marriage (Hebrew yibbum): when brothers dwell together and one dies childless, the surviving brother "shall go in unto her, and take her to him to wife," so that the firstborn "shall succeed in the name of his brother which is dead, that his name be not put out of Israel." Leviticus 20:21 declares the seemingly identical act forbidden: "if a man shall take his brother's wife, it is an unclean thing (niddah); he hath uncovered his brother's nakedness; they shall be childless." The Hebrew niddah ordinarily denotes menstrual impurity and by extension abhorrent defilement, and the prescribed consequence — childlessness ("riyriym, 'stripped/childless') — is thematically barbed: it is the precise outcome the Deuteronomic levirate exists to prevent.
The most natural source-critical placement is that Leviticus 20:21 belongs to the Holiness Code (H, Lev 17-26), whose incest catalogue in Leviticus 18 prohibits "uncovering the nakedness" of a long list of kin defined through a male relative — father's wife, daughter-in-law, and at 18:16 "thy brother's wife." H's logic is genealogical and cultic: such unions defile the land. Deuteronomy 25 (D) operates from a different concern — the preservation of the dead man's name, line, and property within the patrimony. Two legal traditions, two priorities, one act.
The strongest harmonization, defended by Archer and by John Walton, restricts the Levitical prohibition to a brother's wife while the brother is alive, making it a prohibition of adultery and incest within a living union, and reserves Deuteronomy 25 for the widow of a brother who has died childless. This reading has real support: Leviticus 18:16's parallel sits in a list otherwise concerned with relations that would constitute adultery or rivalry within the extended household, and Jacob Milgrom argues that 18:16 indeed contemplates the wife of a living brother. The reading thus resolves the parallel at 18:16 cleanly. The difficulty is that Leviticus 20:21 itself does not specify the brother's state, and its penalty clause (childlessness) is most pointed precisely if the union in view is one undertaken after a brother's death to produce children — which is exactly the levirate situation. If H simply meant adultery with a living brother's wife, the death penalty applied elsewhere in the chapter to adultery (Lev 20:10) would be expected, not the distinctive sentence of childlessness.
The rabbinic tradition itself conceded a real conflict and resolved it by legislative arbitration rather than by claiming the laws never overlapped. The Mishnah's entire tractate Yebamot is devoted to defining when the Deuteronomic levirate obligation overrides the general Levitical prohibition of a brother's wife, concluding that the mitzvah of yibbum suspends the prohibition only in the precise case of a childless widow, and that outside that case the prohibition stands with full force. That is not the harmony of two laws that never touched; it is a ruling about which of two genuinely competing statutes prevails in a defined situation. The narrative tradition assumes levirate duty as normative and praiseworthy — Genesis 38 (Tamar, Judah, and the failure of Onan) and the book of Ruth both turn on the obligation to raise up seed for a dead kinsman.
Where the critical reading lands: a real legal tension between H and D that the case-distinction harmonization can partly but not fully dissolve; the rabbis themselves treated it as a conflict requiring one law to override the other.
Sources for this reading