Two men brought a dispute before the Prophet ﷺ, and the oath fell upon one of them. He swore by Allah, beside whom there is no god, that he owed the other nothing.Then Jibreel descended upon the Prophet ﷺ and said, "He is lying. He does indeed owe him what is due."So the Prophet ﷺ ordered him to give the man his due, and the expiation for his false oath was his acknowledgment that there is no god but Allah, or his testimony to that.
حدثنا أسود بن عامر حدثنا شريك عن عطاء بن السائب عن أبي يحيى الأعرج
اختصم إلى النبي ﷺ رجلان فوقعت اليمين على أحدهما فحلف بالله الذي لا إله إلا هو ما له عنده شيء قال فنزل جبريل على النبي ﷺ فقال إنه كاذب إن له عنده حقه فأمره أن يعطيه حقه وكفارة يمينه معرفته أن لا إله إلا الله أو شهادته