(3) باب نَدْبِ مَنْ حَلَفَ يَمِينًا فَرَأَى غَيْرَهَا خَيْرًا مِنْهَا أَنْ يَأْتِيَ الَّذِي هُوَ خَيْرٌ وَيُكَفِّرَ عَنْ يَمِينِهِ
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
He who took an oath and then found another thing better than (this) should expiate for the oath (broken) by him and do (the better thing).
Reference: Sahih Muslim 1650 b
In-book reference: Book 27, Hadith 19
USC-MSA web (English) reference(deprecated numbering scheme): Book 15, Hadith 4053