كتاب الفضائل
9
The Book of Virtues
'Aishah (may Allah be pleased with her) reported:
We used to prepare for the Messenger of Allah (ﷺ) a Miswak (tooth-stick) and the water for making Wudu'. Whenever Allah wished to awaken him from sleep at night, he (ﷺ) would brush his teeth with Miswak, make Wudu', and perform Salat.

[Muslim].

وعن عائشة رضي الله عنها، قالت‏:‏ كنا نعد لرسول الله، سواكه وطهوره، فيبعثه الله ما شاء أن يبعثه من الليل، فيتسوك ويتوضأ ويصلي‏.‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏
Sunnah.com reference : Book 9, Hadith 208
Arabic/English book reference : Book 9, Hadith 1198