Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
tabarani:20091ʿAlī b. ʿAbd al-ʿAzīz > al-Qaʿnabī > ʿAbd al-Raḥman b. Abū al-Mawāl > ʿAbdullāh b. al-Ḥasan > Um Salamah

[Machine] Al-Qa'ani narrated that Abdul Rahman ibn Abi Al-Mawali reported from Abdullah ibn Al-Hasan who reported from Umm Salamah that she swore an oath regarding a slave whom she had freed. She said, "May Allah never free him from the Fire if I were to free him." Then she stayed until Allah willed. She said, "Glory be to Allah! I heard the Messenger of Allah ﷺ say, 'Whoever takes an oath and then sees something better, let him expiate for his oath and do what is better.'" So I freed the slave and expiated for my oath.  

الطبراني:٢٠٠٩١حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ الْعَزِيزِ

ثنا الْقَعْنَبِيُّ ثنا عَبْدُ الرَّحْمَنِ بْنُ أَبِي الْمَوَالِ عَنْ عَبْدِ اللهِ بْنِ الْحَسَنِ عَنْ أُمِّ سَلَمَةَ أَنَّهَا حَلَفَتْ فِي غُلَامٍ لَهَا اسْتَعْتَقَهَا قَالَتْ لَا أَعْتَقَهَا اللهُ مِنَ النَّارِ إِنْ أَعْتَقَتْهُ أَبَدًا ثُمَّ مَكَثَتْ مَا شَاءَ اللهُ فَقَالَتْ سُبْحَانَ اللهِ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ حَلَفَ عَلَى يَمِينٍ فَرَأَى خَيْرًا مِنْهَا فَلْيُكَفِّرْ عَنْ يَمِينِهِ ثُمَّ لِيَفْعَلِ الَّذِي هُوَ خَيْرٌ» فَأَعْتَقْتُ الْعَبْدَ ثُمَّ كَفَّرْتُ عَنْ يَمِينِهَا