وَعَنْ حُذَيْفَةَ
قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: إِذَا قَامَ لِلتَّهَجُّدِ مِنَ اللَّيْلِ يَشُوصُ فَاهُ بِالسِّوَاكِ
When the Prophet (sallallahu alayhi wa sallam) got up to pray during the night he cleansed his mouth with the tooth-stick.
Mishkat al-Masabih 352, Book 4, Purification, Hadith 88. 1 min read