yamīn ghamūs, so called because it plunges a person first into sin and then into the Fire. No expiation is prescribed for it, for it is too grave to be atoned for and counts among the major sins.

If someone utters words of oath unintentionally—such as saying, “No, by Allah,” or “Yes, by Allah,” with no intention of actually swearing—this is considered idle speech and entails no expiation. Allah, Exalted is He, says, “Allah will not call you to account for idle talk in your oaths” (Qur’an 2:225). ʿĀʾishah reported that the Messenger of Allah ﷺ said, “The idle oath is a man’s casual words among his people: ‘No, by Allah,’ and ‘Yes, by Allah.’” Abū Dāwūd narrated this report.

The ruling is the same when a person deliberately swears, assuming he is truthful, only to discover later that he was mistaken.

Shaykh al-Islām Ibn Taymiyyah said, “Similarly, if someone binds an oath about a future matter, thinking he is telling the truth, but it turns out otherwise, he is not like one who swears concerning another person, assuming that person will comply, yet the latter does not.”

Condition Two: The oath must be taken voluntarily. If a person is coerced into swearing, the oath is not valid, for the Prophet ﷺ said, “My community has been pardoned for what they do by mistake, out of forgetfulness, or under coercion.” This shows that anyone forced to swear is excused.