Bukhari :: Book 3 :: Volume 31 :: Hadith 225
Narrated Salama bin Al-Akwa:
The Prophet ordered a man from the tribe of Bani Aslam to announce amongst the people that whoever had eaten should fast the rest of the day, and whoever had not eaten should continue his fast, as that day was the day of 'Ashura' .
Source materials are from the University of Southern California MSA site|
Hadith eBooks converted from Imaan Star