جَامِعُ التِّرْمِذِيِّ
Jami‘ at-Tirmidhi 760
The Book on Fasting
What Has Been Related About Fasting Three (Days) Of Every Month
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ سِمَاكِ بْنِ حَرْبٍ، عَنْ أَبِي الرَّبِيعِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ عَهِدَ إِلَىَّ النَّبِيُّ صلى الله عليه وسلم ثَلاَثَةً أَنْ لاَ أَنَامَ إِلاَّ عَلَى وِتْرٍ وَصَوْمَ ثَلاَثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ وَأَنْ أُصَلِّيَ الضُّحَى .
Abu Hurairah narrated: "The Messenger of Allah took a covenant from me for three: To not sleep except after performing Witr, to fast three days of every month, and to perform the Duha prayer."
Jami` at-Tirmidhi, 760Hasan (Darussalam)