Chapter on the Rulings on Forgetfulness (Ahkam al-Sahw)
Tahdhīb al-Aḥkām|Volume 2|Book 1|Chapter 16
عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ اِبْنِ أَبِي عُمَيْرٍ عَنْ عُمَرَ بْنِ أُذَيْنَةَ عَنِ اَلْفُضَيْلِ بْنِ يَسَارٍ عَنْ أَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ: فِي اَلرَّجُلِ يُصَلِّي اَلرَّكْعَتَيْنِ مِنَ اَلْمَكْتُوبَةِ ثُمَّ يَنْسَى فَيَقُومُ قَبْلَ أَنْ يَجْلِسَ بَيْنَهُمَا قَالَ« فَلْيَجْلِسْ مَا لَمْ يَرْكَعْ وَ قَدْ تَمَّتْ صَلاَتُهُ وَ إِنْ لَمْ يَذْكُرْ حَتَّى يَرْكَعَ فَلْيَمْضِ فِي صَلاَتِهِ فَإِذَا سَلَّمَ نَقَرَ ثِنْتَيْنِ وَ هُوَ جَالِسٌ»
Ali ibn Ibrahim from his father from Ibn Abi Umayr from ‘Umar ibn Udhaynah from al-Fudayl ibn Yasar:
Abu Ja‘far عليه السلام, peace be upon him, (was asked) regarding a man who prays the first two rak‘ahs of an obligatory prayer, then forgets and stands up before sitting between them. Imam عليه السلام said: "Then let him sit down as long as he has not yet bowed, and his prayer is complete. But if he does not remember until after he has bowed, then let him continue in his prayer. When he finishes with the salam, he should peck out (quickly perform) two (rak‘ahs) while sitting."
- Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 371
- Ṣaḥīḥ al-Tahdhīb, p. 231