Abdullah bin Abbas reported,

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 the other had no claim against him.Then Jibreel descended and said, "Command him to give the man his due, for the right is owed by him and he has lied. The expiation for his oath is his acknowledgment of Allah that there is no god but He," or, "his testimony that there is no god but He."

Ahmad 2956

Daif

حدثنا هاشم بن القاسم حدثنا شريك عن عطاء بن السائب عن أبي يحيى الأعرج

عن ابن عباس قال

اختصم رجلان فدارت اليمين على أحدهما فحلف بالله الذي لا إله إلا هو ما له عليه حق فنزل جبريل فقال مره فليعطه حقه فإن الحق قبله وهو كاذب وكفارة يمينه معرفته بالله أنه لا إله إلا هو أو شهادته أنه لا إله إلا هو

أحمد 2956ضعيف
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Abdullah bin Abbas bin Abdul-Muttalib
Numbering
Darussalam 2956
Ahmad 2956