Is an oath taken regarding an act impossible by reason legally binding?
General Chapter
Al-Mughni
Book of Oaths
Primary text
According to Abu Al-Khattab, an oath concerning an act impossible by reason, such as turning back yesterday or drinking water from an empty jug, is not legally binding, and no expiation is due. This position is also the Madhhab of Malik, based on the reasoning that the oath is coupled with something that dissolves it, thus preventing its establishment, similar to an oath of perjury (yamin al-ghumus), or an oath concerning something inconceivable, which resembles the oath of perjury. This is because an oath is only established upon something conceivable or something whose conceivability is merely supposed.
Supporting text
Al-Qadi holds that the oath regarding an act impossible by reason is established and necessitates immediate expiation. This is the position of Abu Yusuf and Al-Shafi'i. Their evidence is that the oath concerns the person's future action, which has not occurred, analogous to swearing to divorce a wife who subsequently dies before the divorce is pronounced. They also apply the ruling by analogy to acts impossible by custom, asserting there is no difference whether the impossibility is known or unknown by the swearer, such as swearing to drink water from an empty jug.