(9) باب طُولِ الْقِيَامِ فِي صَلاَةِ اللَّيْلِ
Narrated Hudhaifa:
Whenever the Prophet (ﷺ) got up for Tahajjud prayer he used to clean his mouth (and teeth) with Siwak. (AR)
Reference (AR): Sahih al-Bukhari 1136 (AR)
In-book reference (AR): Book 19, Hadith 17 (AR)
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 21, Hadith 237 (AR)