The Chapter of Siwak
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 12
وَقَالَ اَلنَّبِيُّ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ: «اِكْتَحِلُوا وَتْراً وَ اِسْتَاكُوا عَرْضاً.
The Prophet, said: "Apply kohl in an odd number of strokes and use siwak (tooth cleaning) across the width of the mouth”.
- Ṣaḥīḥ al-Faqīh