Riyad as-Salihin
Riyad as-Salihin 1264
The Desirability of Observing Three Days of Fasting in Every Month
Arabic hadith text
وعن ابن عباس، رضي الله عنهما، قال: كان رسول الله صلى الله عليه وسلم "لا يفطر أيام البيض في حضر ولا سفر" ((رواه النسائي بإسناد حسن)).
Translation
Ibn 'Abbas (May Allah be pleased with them) reported
It was the practice of the Messenger of Allah (ﷺ) to not to omit fast on 'bright days' whether he was staying at a place or on a journey.[An-Nasa'i].