´It was narrated that Abu Dharr said:` "The Messenger of Allah commanded us to fast the three days of Al-Bid, the thirteenth, fourteenth and fifteenth."
Hadith ReferenceSunan an-Nasa'i / The Book of Fasting / Hadith: 2424
Hadith Gradingالألبانی:حسن | زبیر علی زئی:إسناده حسن