حَدَّثَنِي يَزِيدُ يَعْنِي ابْنَ هَارُونَ أَخْبَرَنَا شَرِيكُ بْنُ عَبْدِ اللَّهِ عَنْ أَبِي إِسْحَاقَ عَنِ التَّمِيمِيِّ عَنِ ابْنِ عَبَّاسٍ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أُمِرْتُ بِالسِّوَاكِ حَتَّى ظَنَنْتُ أَوْ حَسِبْتُ أَنْ سَيَنْزِلُ فِيهِ قُرْآنٌ
مسند امام احمد بن حنبل · Hadith 2125
It was narrated that Ibn 'Abbas (RA) said: The Messenger of Allah (PBUH) said: "I was commanded to use the siwak until I thought - or I expected - that Qur'an would be revealed to me concerning it."
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020