Sahih al-Bukhari 4680
صحيح البخاري#4680SahihNarrated Ibn `Abbas:When the Prophet (ﷺ) arrived at Medina, the Jews were observing the fast on 'Ashura' (10th of Muharram) and they said, "This is the day when Moses became victorious over Pharaoh," On that, the Prophet (ﷺ) said to his companions, "You (Muslims) have more right to celebrate Moses' victory than they have, so observe the fast on this day
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 65:202