Chapter on the Description of Ablution (Wudu)
Tahdhīb al-Aḥkām|Volume 1|Book 1|Chapter 4
وَ اَلْخَبَرُ اَلْآخَرُ اَلَّذِي رَوَاهُ أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ صَفْوَانَ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ قَالَ:« اَلْوُضُوءُ مَثْنَى مَثْنَى».
As for the other report narrated by Ahmad ibn Muhammad, from Ṣafwan, from Abu Abdullah عليه السلام, who said:
Imam عليه السلام said: "Ablution (Wuduʾ) is twice for each part."
- Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 83
- Ṣaḥīḥ al-Tahdhīb