Is it permissible to swear an oath by anything other than Allah (God)?
General Chapter
Al-Mughni
Book of Oaths
Primary text
It is not permissible to swear an oath by anything other than Allah, including His attributes, such as swearing by one's father, the Kaaba, a companion (Sahabi), or an Imam. Imam Shafi'i feared this act constitutes a sin, and Ibn Abd al-Barr stated this is an established point of consensus. The primary evidence against this practice is the report from Umar ibn al-Khattab that the Prophet, peace and blessings be upon him, forbade swearing by fathers, commanding that one should swear only by Allah or remain silent. Omar subsequently ceased swearing by his father. Furthermore, the Prophet, peace and blessings be upon him, stated, "Whoever swears by other than Allah has committed Shirk (associating partners with Allah)." Another hadith states that whoever swears by Al-Lat and Al-Uzza should say, "There is no god but Allah."
Supporting text
A view exists permitting swearing by created beings because Allah Almighty swore by His creations in the Quran, such as {By the ranks [of the angels] arranged in rows} (Quran 37:1), {And [by] those sent forth in succession} (Quran 77:1), and {And [by] those who drag forth with vigor} (Quran 79:2). Additionally, the Prophet, peace and blessings be upon him, swore by his father in response to an inquirer. However, this view is refuted by stating that Allah's oath serves to demonstrate His power and greatness, and analogy cannot be drawn from His oath to His creation. Moreover, the reported instances of the Prophet swearing by created things are deemed either unpreserved through sound chains or superseded by later explicit prohibition, as demonstrated by Omar's subsequent cessation of the practice.