Sunan Ibn Majah 2104
سنن ابن ماجه#2104Sahihحَدَّثَنَا الْعَبَّاسُ بْنُ عَبْدِ الْعَظِيمِ الْعَنْبَرِيُّ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَنْبَأَنَا مَعْمَرٌ، عَنِ ابْنِ طَاوُسٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ حَلَفَ فَقَالَ إِنْ شَاءَ اللَّهُ فَلَهُ ثُنْيَاهُ " .
It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:'Whoever swears an oath and says In sha' Allah, he will have made an exception
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 11:15