رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1717
The Book of the Prohibited actions
Desirability of Expiating the Oath taken by a Person who afterwards Breaks it for a better Alternative
وَعَنْ أَبِي مُوسَى رَضِيَ اللَّه عَنْهُ أَنَّ رَسُولَ اَللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ قَالَ: إِنِّي وَاللَّهِ إِنْ شَاءَ اللَّهُ لاَ أَحْلِفُ عَلَى يَمِينٍ، ثُمَّ أَرَى خَيْرًا مِنْهَا إِلاَّ كَفَّرْتُ عَنْ يَمِينِي، وَأَتَيْتُ الَّذِي هُوَ خَيْرٌ . ((مُتَّفَقٌ عَلَيْهِ))
Abu Musa (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "Verily, I swear by Allah, if Allah wills, I shall not swear to do something but that if I consider something else to be better than it, then I shall make expiation for my oath and adopt the thing that is better." [Al-Bukhari and Muslim].
Riyad as-Salihin, 1717