‘Aishah رضّى الله عنها narrated that the Prophet صلى الله عليه وسلم said:
السواك مطهرة للفم مرضاة للرب
“The miswak purifies (cleanses) the mouth and is pleasing to the Rabb.”
[An-Nasa’i, 5; Musnad Ahmad, 23652; Ibn Khuzaymah, 141; Ibn Hibban, 1081, Tabarani and others – graded as saheeh by majority]
Ali رضي الله عنه has been reported to have said:
إن أفواهكم طرق القرآن فطيبوها بالسواك
Verily, your mouths are paths of the Qur’an, so brush them clean.
[Ibn Majah, 287; Al-Bazzar, who said the sanad was jayyid; graded as Saheeh by al-Albani in ‘Saheeh ibn Majah’, 239]