Is the declaration of making something permissible unlawful upon oneself considered a binding oath (Yamin)?
General Chapter
Al-Mughni
Book of Oaths
Primary text
The declaration of making something lawful unlawful upon oneself constitutes an oath requiring expiation. This is supported by the Almighty’s saying: 'O Prophet, why do you prohibit yourself what Allah has made lawful for you?' (Quran 28:1) leading to the verse that names the expiation of oaths: 'Allah has already ordained for you the dissolution of your oaths' (Quran 66:2). This indicates that prohibiting what Allah has made lawful is termed an oath, requiring expiation. The narration from Aisha, may Allah be pleased with her, concerning the incident of the Prophet (PBUH) drinking honey, which prompted the revelation of Quran 66:1, supports this interpretation. Furthermore, it is narrated from Ibn Abbas and Ibn Umar that the Prophet (PBUH) considered prohibiting the lawful an oath. Even if the verse were revealed concerning the prohibition of Maria al-Qibtiyya (as suggested by Al-Hasan and Qatadah), establishing expiation for prohibiting her—a lawful non-wife—implies that expiation is required for prohibiting any lawful matter by analogy.
Supporting text
Some hold that the verse was revealed concerning the prohibition of Maria al-Qibtiyya, but the view citing Aisha’s immediate presence at the revelation is deemed sounder. If the ruling is confirmed regarding Maria, it serves as proof that prohibiting any lawful item necessitates expiation, which invalidates other arguments made by Al-Hasan and Qatadah. Malik and Al-Shafi'i hold that it is not an oath and no expiation is due because the intent was to alter the prescribed law, thereby nullifying the intent, similar to saying, 'This is my stepdaughter.'