The Limits of Ablution, Its Order and Reward
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 11
وَ رُوِيَ: «أَنَّ مَنْ تَوَضَّأَ فَذَكَرَ اِسْمَ اَللَّهِ طَهُرَ جَمِيعُ جَسَدِهِ وَ كَانَ اَلْوُضُوءُ إِلَى اَلْوُضُوءِ كَفَّارَةً لِمَا بَيْنَهُمَا مِنَ اَلذُّنُوبِ وَ مَنْ لَمْ يُسَمِّ لَمْ يَطْهُرْ مِنْ جَسَدِهِ إِلاَّ مَا أَصَابَهُ اَلْمَاءُ.
It is narrated: 'Whoever performs ablution and mentions the name of Allah سبحانه وتعالى, all of his body becomes pure, and the ablution performed between two ablutions serves as atonement for the sins committed between them. And whoever does not mention [the name of Allah سبحانه وتعالى] will not purify his body except for what the water touches.'"
- Ṣaḥīḥ al-Faqīh