The Chapter of Siwak
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 12
وَقَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: «فِي اَلسِّوَاكِ اِثْنَتَا عَشْرَةَ خَصْلَةً هُوَ مِنَ اَلسُّنَّةِ وَ مَطْهَرَةٌ لِلْفَمِ وَ مَجْلاَةٌ لِلْبَصَرِ وَ يُرْضِي اَلرَّحْمَنَ وَ يُبَيِّضُ اَلْأَسْنَانَ وَ يَذْهَبُ بِالْحَفْرِ وَ يَشُدُّ اَللِّثَةَ وَ يُشَهِّي اَلطَّعَامَ وَ يَذْهَبُ بِالْبَلْغَمِ وَ يَزِيدُ فِي اَلْحِفْظِ وَ يُضَاعِفُ اَلْحَسَنَاتِ وَ تَفْرَحُ بِهِ اَلْمَلاَئِكَةُ.
Imam Jafar ibn Muhammad Al-Sadiq عليه السلام said: "Siwak (tooth cleaning) has twelve benefits: it is part of the Sunnah (tradition), purifies the mouth, improves vision, pleases the Merciful, whitens the teeth, removes decay, strengthens the gums, increases appetite, removes phlegm, enhances memory, multiplies good deeds, and brings joy to the angels."
- Ṣaḥīḥ al-Faqīh