Hadith 707
707 - حَدَّثَنَا الْحُمَيْدِيُّ قَالَ: ثنا سُفْيَانُ، قَالَ: ثنا أَيُّوبُ السِّخْتِيَانِيُّ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّي اللهُ عَلَيْهِ وَسَلَّمَ: " مَنْ حَلَفَ، فَقَالَ: إِنْ شَاءَ اللَّهُ تَعَالَي فَقَدِ اسْتَثْنَي "
Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: The Noble Prophet (peace and blessings of Allah be upon him) said: "Whoever says 'In sha Allah' while taking an oath, then that person has made an exception."