As for “swearing by created things”—such as the Kaaba, a shaykh’s grave, the sultan’s favour, a sword, or the standing of any created being—I know of no disagreement among the scholars that such oaths are disapproved of and forbidden, and that breaking them entails neither liability for oath-breaking nor expiation. Is swearing by them unlawful, or merely discouraged without being unlawful? There are two opinions in the school of Ahmad and among other scholars; the more correct is that it is unlawful.

For this reason, our scholars, such as al-Qādī Abū Ya‘lā and others, said that if someone says, “The oaths of the Muslims shall be binding upon me if I do such-and-such,” he is bound by the requirements applicable to oaths by Allah, vows, divorce, manumission and zihār. They did not mention oaths invoking prohibition, because, according to Ahmad and his followers, an oath invoking prohibition constitutes zihār. Since both entail the same consequence in their view, prohibition was included under zihār.

Vows, however, were not included under oaths by Allah, even though one may offer expiation for an oath invoking a vow. This is because, when an oath invoking a vow—known as a “vow of obstinacy and anger”—is broken, one has the choice between offering expiation and fulfilling the vow, whereas breaking an oath by Allah requires expiation alone. Since their consequences differ, they treated them as two distinct kinds of oath. However, if they adopt the other position reported from Ahmad—that an oath invoking a vow requires expiation alone—then an oath invoking a vow is included under an oath by Allah Most High.

As for their disagreement, and that of other scholars, over whether wording of this kind constitutes a binding oath, I shall discuss it, Allah Most High willing. My purpose here is only to enumerate the kinds of oath sworn by Muslims.

As for oaths of allegiance, they said that the first to introduce them was al-Hajjāj ibn Yūsuf al-Thaqafī. The established practice had been for people to pledge allegiance to the caliphs as the Companions had pledged allegiance to the Prophet, may Allah bless him and grant him peace