Volume 6, Book 60, Number 261:
Narrated Ibn Abbas:
When Allah’s Apostle arrived at Medina, he found the Jews observing the fast on the day of
‘Ashura’ (10th of Muharram). The Prophet asked them (about it) and they replied, “This is the day
when Moses became victorious over Pharaoh.” The Prophet said (to the Muslims), “We are nearer to
Moses than they, so fast on this day.”