Messenger of Allah, why is it that you select (your wife) from among the Quraish, but you ignore us (the nearest of the kin)? Thereupon he said: Have you anything for me (a suitable match for me)? I said; Yes, the daughter of Hamza, whereupon Allah's Messenger (ﷺ) said: She is not lawful for me, for she is the daughter of my brother by reason of fosterage.
The Book of Suckling - Sahih Muslim 1446a
This narration from Sahih Muslim establishes a fundamental principle in Islamic family law regarding foster relationships and marriage prohibitions.
Context and Question
A companion questioned the Prophet Muhammad (ﷺ) about his marriage preferences, noting that he selected wives from Quraish while ignoring closer kin. This reflects the companion's desire for closer familial connection through marriage.
Legal Ruling Explained
The Prophet clarified that the daughter of his paternal uncle Hamza (may Allah be pleased with him) was prohibited for marriage because she was considered his foster daughter. Foster relationships create the same marriage prohibitions as blood relationships in Islamic law.
Scholarly Commentary
Classical scholars explain that fosterage (radāʿah) through suckling establishes permanent mahram relationships. Just as one cannot marry one's biological daughter, one cannot marry one's foster daughter. This hadith demonstrates that foster brotherhood is equivalent to blood brotherhood in terms of marriage prohibitions.
The ruling applies regardless of whether the foster relationship occurred in infancy or through minimal suckling, as established in other authentic narrations.
Practical Implications
This teaching safeguards family honor and prevents confusion in lineage. It emphasizes that Islamic marriage laws consider both blood and foster relationships equally in determining lawful and unlawful marital partners.