The Prophet ﷺ said, "The siwak is a means of purifying the mouth and pleasing the Lord."
عن النبي ﷺ قال: السواك مطهرة للفم، مرضاة للرب.
Nasai (5) reported it, saying, Humayd bin Masada Basri and Muhammad bin Abdul-Ala told us, from Yazid, who is Ibn Zuray, who said, Abdul-Rahman bin Abu Atiq told me, saying, my father told me, saying, I heard Ayesha narrating, and he then mentioned the hadith. Its isnad is sahih, and Bukhari mentioned it without a full chain in Sahih Bukhari (4/158), with Fath al-Bari, using a definitive phrasing. Ibn Khuzayma (135) and Ibn Hibban (1067) graded it sahih. See Minna Kubra (1/121).Ibn Abu Atiq is Abdullah bin Muhammad bin Abdul-Rahman bin Abu Bakr Siddiq, and Muhammad's kunya is Abu Atiq. Bayhaqi (1/34) said, "Abdul-Rahman bin Abdullah narrated it likewise from his father, and he made clear in it that his father had heard it directly." He then reported it through his chain, and cited other isnads for it. Ahmad (7 and 62) and Abu Yaala (1/86, no. 104) reported it, placing it within the Musnad of Abu Bakr, but the correct view is that it belongs to the Musnad of Ayesha. See Ilal by Ibn Abu Hatim (1/12) and Fath al-Bari (4/158–159).