That the Messenger of Allah ﷺ said: "Whoever swears about an oath and says: 'If Allah wills (Insha Allah), then there is no breaking of the oath against him."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ حَلَفَ عَلَى يَمِينٍ فَقَالَ إِنْ شَاءَ اللَّهُ فَقَدِ اسْتَثْنَى فَلاَ حِنْثَ عَلَيْهِ قَالَ وَفِي الْبَابِ عَنْ أَبِي هُرَيْرَةَ  

That the Messenger of Allah ﷺ said: "Whoever swears [about an oath] and says: 'If Allah wills (Insha Allah), then he will not have broken it."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ حَلَفَ عَلَى يَمِينٍ فَقَالَ إِنْ شَاءَ اللَّهُ لَمْ يَحْنَثْ