Volume 9, Book 91, Number 370:
Narrated Salama bin Al-Akwa’:
Allah’s Apostle said to a man from the tribe of Al-Aslam, “Proclaim among your people (or the
people) on the day of ‘Ashura’ (tenth of Muharram), ‘Whosoever has eaten anything should fast for
the rest of the day; and whoever has not eaten anything, should complete his fast.’ “