Muhammad ibn Bishr narrated to us; ʿAbdullāh transmitted it, from Nāfiʿ, from Ibn ʿUmar (may Allah be pleased with him): “The inscription on the signet of the Messenger of Allah ﷺ read: ‘Muhammad, Messenger of Allah.’”

Imam Abū ʿAbdullāh (may Allah have mercy on him) added: The Prophet ﷺ also dispatched a letter that began, “In the name of Allah, the All-Merciful, the Especially Merciful.” Caesar’s interpreter read it aloud to Caesar and his courtiers. We have no doubt that the act of reading performed by the unbelievers and the People of the Book is their own deed, whereas the words recited are the speech of Allah, the Mighty, the Bestower—uncreated.

Accordingly, should anyone swear by mere exclamations or by the call employed by the polytheists who nonetheless acknowledge Allah, no binding oath is incurred unless he swears by Allah Himself, because the Prophet ﷺ said, “Do not swear by anything other than Allah.” Likewise, no one is permitted to swear by signet-rings, silver dirhams, or the wooden tablets on which children write and which they erase time and again; but if he does so, the oath is not binding upon him, for Allah says: “So do not set up rivals to Allah” (al-Baqarah 2:22).