Al-Kāfi

Hadith 123
wudu
6ـ مُحَمَّدُ بْنُ الْحَسَنِ وَغَيْرُهُ عَنْ سَهْلِ بْنِ زِيَادٍ عَنِ ابْنِ مَحْبُوبٍ عَنِ ابْنِ رِبَاطٍ عَنْ يُونُسَ بْنِ عَمَّارٍ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ الْسَّلام) عَنِ الْوُضُوءِ لِلصَّلاَةِ فَقَالَ مَرَّةٌ مَرَّةٌ.
6. Muhammad ibn al-Hassan and others have narrated from Sahl ibn Ziyad from ibn Mahbub from ibn Ribat from Yunus ibn ‘Ammar who has said the following: “I once asked abu ‘Abd Allah (a.s.), about Wudu’ for Salah (prayer). He (the Imam) said, ‘It is (washing the face) once and (hands) once.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī