The verses of li'an (mutual imprecation)
6–9
As narrated in Bukhari, Hilal b. Umayya accused his wife of adultery with Sharik b. Sahma. When the Prophet said, “Either you bring proof or the prescribed punishment falls on your back,” Hilal replied, “O Messenger of Allah, if one of us sees a man with his wife, is he to go looking for proof?” Thereupon the verses regulating li'an — the sworn testimony of a husband who accuses his wife without witnesses — were revealed, and the two performed li'an in the mosque. In the report of Sahl b. Sa'd a similar incident is related about Uwaymir al-Ajlani; scholars have discussed which of the two cases occasioned the verses, some holding that both may have.
Buhârî 4747, 5259; Müslim 1492
Revelation context of the surah
Surah-wide
An-Nur is Medinan; its best-known section comprises the verses revealed concerning the slander against Aisha on the return from the Banu Mustaliq campaign (the Ifk incident, around 5-6 AH). It legislates on safeguarding chastity, the penalty for slanderous accusation, modest dress, and the etiquette of privacy in family and social life.
Buhârî ve Müslim rivayetleri; klasik tefsir mukaddimeleri