´'Abdur-Rahman bin Abu 'Atiq said:` "My father told me: 'I heard 'Aishah say, (narrating) from the Prophet (ﷺ): "Siwak is a means of purification for the mouth and is pleasing to the Lord."
Hadith Referenceسنن نسائي / كتاب الطهارة / 5
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح مشكوة المصابيح: 381