حَدَّثَنَا سُفْيَانُ عَنْ أَيُّوبَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ يَبْلُغُ بِهِ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ حَلَفَ عَلَى يَمِينٍ فَقَالَ إِنْ شَاءَ اللَّهُ فَقَدْ اسْتَثْنَى
مسند امام احمد بن حنبل · Hadith 4581
It was narrated from Naafi', from Ibn Umar, who attributed it to the Prophet (PBUH) "Whoever swears an oath and says. In sha Allah cannot break his oath (whether he goes ahead and fulfils the oath or not).
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020