What constitutes a detested oath?
General Chapter
Al-Mughni
Book of Oaths
Primary text
The detested oath is that sworn regarding performing a detested act or abandoning a recommended act. This falls under the prohibition of making God an excuse to avoid righteousness or reconciliation (Quran 2:224). Abu Bakr al-Siddiq swore not to continue supporting Misthah after the incident concerning Aisha, and the verse regarding those of wealth not swearing to withhold from relatives and the needy was revealed. Such an oath is detested because it either prevents obedience or compels the performance of something disliked, thus taking the ruling of the matter sworn upon.
Supporting text
The oath of the Bedouin who swore only to perform the prescribed five daily prayers and no more was not denied by the Prophet, because swearing to adhere to the obligatory is highly favored and trumps the abandonment of the voluntary component, placing it closer to the recommended category.