Chapter on the Description of Ablution (Wudu)
Tahdhīb al-Aḥkām|Volume 1|Book 1|Chapter 4
وَ بِهَذَا اَلْإِسْنَادِ عَنِ اَلْحُسَيْنِ بْنِ سَعِيدٍ عَنِ اَلْقَاسِمِ بْنِ عُرْوَةَ عَنِ اِبْنِ بُكَيْرٍ عَنْ زُرَارَةَ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ :فِي اَلرَّجُلِ يَنْسَى مَسْحَ رَأْسِهِ حَتَّى يَدْخُلَ فِي اَلصَّلاَةِ قَالَ« إِنْ كَانَ فِي لِحْيَتِهِ بَلَلٌ بِقَدْرِ مَا يَمْسَحُ رَأْسَهُ وَرِجْلَيْهِ فَلْيَفْعَلْ ذَلِكَ وَ لْيُصَلِّ» قَالَ« وَ إِنْ نَسِيَ شَيْئاً مِنَ اَلْوُضُوءِ اَلْمَفْرُوضِ فَعَلَيْهِ أَنْ يَبْدَأَ بِمَا نَسِيَ وَ يُعِيدَ مَا بَقِيَ لِتَمَامِ اَلْوُضُوءِ».
Through the same chain of transmission, from al-Husayn ibn Saʿid, from al-Qasim ibn ʿUrwah, from Ibn Bukayr, from Zurarah, from Abu Abdullah عليه السلام,
Imam عليه السلام said regarding a man who forgets to wipe his head until he enters into prayer: "If there is moisture in his beard sufficient to wipe his head and feet, he should do so and then continue his prayer." Imam عليه السلام further said: "If someone forgets any part of the obligatory Wuduʾ, they must perform what they forgot and repeat the remaining parts to complete the Wuduʾ."
- Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 92
- Ṣaḥīḥ al-Tahdhīb, p. 56