Chapter on the Rulings on Forgetfulness (Ahkam al-Sahw)
Tahdhīb al-Aḥkām|Volume 2|Book 1|Chapter 16
سَعْدٌ عَنْ مُحَمَّدِ بْنِ اَلْحُسَيْنِ عَنْ مُوسَى بْنِ عُمَرَ عَنْ مُوسَى بْنِ عِيسَى عَنْ مَرْوَانَ بْنِ مُسْلِمٍ عَنْ عَمَّارِ بْنِ مُوسَى اَلسَّابَاطِيِّ قَالَ: سَأَلْتُ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ عَنْ شَيْءٍ مِنَ اَلسَّهْوِ فِي اَلصَّلاَةِ فَقَالَ« أَ لاَ أُعَلِّمُكَ شَيْئاً إِذَا فَعَلْتَهُ ثُمَّ ذَكَرْتَ أَنَّكَ أَتْمَمْتَ أَوْ نَقَصْتَ لَمْ يَكُنْ عَلَيْكَ شَيْءٌ» قُلْتُ بَلَى قَالَ« إِذَا سَهَوْتَ فَابْنِ عَلَى اَلْأَكْثَرِ فَإِذَا فَرَغْتَ وَ سَلَّمْتَ فَقُمْ فَصَلِّ مَا ظَنَنْتَ أَنَّكَ نَقَصْتَ فَإِنْ كُنْتَ قَدْ أَتْمَمْتَ لَمْ يَكُنْ عَلَيْكَ فِي هَذِهِ شَيْءٌ وَ إِنْ ذَكَرْتَ أَنَّكَ كُنْتَ نَقَصْتَ كَانَ مَا صَلَّيْتَ تَمَامَ مَا نَقَصْتَ»
Sa‘d from Muhammad ibn al-Husayn from Musa ibn ‘Umar from Musa ibn Isa from Marwan ibn Muslim from ‘Ammar ibn Musa al-Sabati, who said:
I asked Abu Abdillah عليه السلام, peace be upon him, about something regarding forgetfulness in prayer. Imam عليه السلام said: "Shall I not teach you something that, if you do it, and then afterward remember that you either completed or left something out, there will be nothing upon you?" I said: “Yes.” Imam عليه السلام said: "If you forget, then build upon the greater number (of rak‘ahs). Then, when you finish and give salam, stand and pray what you thought you had left out. If it turns out that you had completed the prayer, then what you prayed afterward is not counted against you. And if you remember that you had actually missed something, then what you prayed afterward completes what was missing."
- Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 375
- Ṣaḥīḥ al-Tahdhīb