ENOfficial
Narrated Ibn 'Umar (RA): "Allah's Messenger (ﷺ) said, "Whoever swears an oath, and then says: "If Allah Wills", he is not held accountable if he breaks it." .
Source: sunnah.com
Other translations
Arabic
وَعَنْ اِبْنِ عُمَرَ رَضِيَ اَللَّهُ عَنْهُمَا; أَنَّ رَسُولَ اَللَّهِ - صلى الله عليه وسلم -قَالَ: { "مَنْ حَلِفِ عَلَى يَمِينٍ فَقَالَ: إِنْ شَاءَ اَللَّهُ, فَلَا حِنْثَ عَلَيْهِ" } رَوَاهُ اَلْخَمْسَةُ 1 . وَصَحَّحَهُ اِبْنُ حِبَّانَ 2 .
sunnah.com