Al-Kāfi
Hadith 8196- عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ الأشْعَرِيِّ عَنِ ابْنِ الْقَدَّاحِ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ قَالَ أَمِيرُ الْمُؤْمِنِينَ (عَلَيْهِ السَّلام) الاسْتِثْنَاءُ فِي الْيَمِينِ مَتَى مَا ذَكَرَ وَإِنْ كَانَ بَعْدَ أَرْبَعِينَ صَبَاحاً ثُمَّ تَلا هَذِهِ الآيَةَ وَاذْكُرْ رَبَّكَ إِذا نَسِيتَ.
6. A number of our people have narrated from Sahl ibn Ziyad from Ja‘far ibn Muhammad al-Ash‘ariy from ibn al-Qaddah who has narrated the following: “Abu ‘Abd Allah (a.s.), has said that ’Amir al-Mu’minin, Ali (a.s.), has said, ‘The forgotten exception in taking an oath must be made even if one remembers after forty mornings.’ He (the Imam) then read this verse, . . speak of your Lord if you forget.’”