Expiation for Unfulfilled Oaths
حَدَّثَنَا أَبُو النُّعْمَانِ، حَدَّثَنَا حَمَّادٌ، وَقَالَ، " إِلاَّ كَفَّرْتُ يَمِينِي، وَأَتَيْتُ الَّذِي هُوَ خَيْرٌ ". أَوْ " أَتَيْتُ الَّذِي هُوَ خَيْرٌ، وَكَفَّرْتُ ".Narrated Hammad:the same narration above (i.e. 709), "I make expiation for my dissolved oath, and I do what is better, or do what is better and make expiation
From Sahih al-Bukhari, whose reports the scholars accept as authentic.