Sahih al-Bukhari 6672
Sahih al-Bukhari · Book 83: Oaths and Vows · If someone does something against his oath due to forgetfulness
Narrated Ubai bin Ka'b:
حَدَّثَنَا الْحُمَيْدِيُّ ، حَدَّثَنَا سُفْيَانُ ، حَدَّثَنَا عَمْرُو بْنُ دِينَارٍ ، أَخْبَرَنِي سَعِيدُ بْنُ جُبَيْرٍ ، قَالَ قُلْتُ لاِبْنِ عَبَّاسٍ فَقَالَ حَدَّثَنَا أُبَىُّ بْنُ كَعْبٍ ، أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صلى الله عليه وسلم {لاَ تُؤَاخِذْنِي بِمَا نَسِيتُ وَلاَ تُرْهِقْنِي مِنْ أَمْرِي عُسْرًا} قَالَ " كَانَتِ الأُولَى مِنْ مُوسَى نِسْيَانًا " .
that he heard Allah's Messenger (ﷺ) saying, "(Moses) said, 'Call me not to account for what I forget and be not hard upon me for my affair (with you)' (18.73) the first excuse of Moses was his forgetfulness."