Islamic law recognizes several permanent barriers to marriage based on close blood relationship, marriage affinity, and milk kinship. Qur’an 4:23 is the central scriptural passage listing many of these relationships. Spiritual Culture summarizes the categories for religious literacy rather than giving personal legal advice, since individual cases can require qualified local scholarship.
Close blood relatives
Qur’an 4:23 prohibits marriage with mothers, daughters, sisters, paternal and maternal aunts, nieces through brothers, and nieces through sisters.
Ascendants and descendants are included
The legal categories extend through direct lines of ancestry and descent. Juristic manuals explain details beyond the shorthand wording used in introductory lists.
Mothers-in-law
A man may not marry his wife’s mother. This prohibition is treated as a permanent affinity relationship in classical Islamic law.
Stepdaughters
Qur’an 4:23 addresses stepdaughters of wives with whom the marriage was consummated. Dar al-Ifta explains that the rule does not depend on whether the stepdaughter literally lives in the same household.
Daughters-in-law
The verse prohibits marriage with wives of one’s biological sons. Classical jurists distinguish biological descent from other social uses of the word son.
Two sisters at the same time
The Qur’an prohibits being married simultaneously to two sisters. This is different from a permanent prohibition on ever marrying the sister of a former spouse after the prior marriage has legally ended and waiting-period rules are satisfied.
Milk kinship
Islamic law recognizes certain breastfeeding relationships as creating marriage barriers. Qur’an 4:23 explicitly mentions milk-mothers and milk-sisters.
Fosterage rules require details
Legal schools discuss the amount, age, and circumstances of breastfeeding that establish raḍāʿa or milk kinship. Families should not infer a ruling from a simplified chart.
Marriage barriers are not the same as ordinary social interaction
A person being mahram concerns marriage eligibility and related rules, but communities still apply norms of respect, privacy, and family responsibility.
Local law and school of jurisprudence matter
Civil marriage law and the Hanafi, Maliki, Shafi‘i, Hanbali, Ja‘fari, and other legal traditions can differ on procedural or interpretive details.
Editorial context
The main Qur’anic framework is clear, but complex family histories should be reviewed by a qualified scholar familiar with the relevant legal school and local law.
