صَحِيحُ مُسْلِمٍ
Sahih Muslim 1650 c
The Book of Oaths
It is recommended for the one who swears an oath then sees that something else is better than it; To do that which is better and offer expiation for his oath
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا ابْنُ أَبِي أُوَيْسٍ، حَدَّثَنِي عَبْدُ الْعَزِيزِ بْنُ الْمُطَّلِبِ، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم مَنْ حَلَفَ عَلَى يَمِينٍ فَرَأَى غَيْرَهَا خَيْرًا مِنْهَا فَلْيَأْتِ الَّذِي هُوَ خَيْرٌ وَلْيُكَفِّرْ عَنْ يَمِينِهِ .
Abu Huraira reported Allah's Messenger (ﷺ) as saying: He who took an oath and (later on) found another thing better than that, he should do that which is better, and expiate for the vow (broken by him).
Sahih Muslim, 1650 cSahihصحيح