Abdur Rahman bin Salamah Khuza'i (RA) narrates from his uncle that the Prophet Muhammad (peace be upon him) said to the people of the tribe of Aslam on the day of Ashura (10th Muharram): "Fast on this day." They said, "We have already eaten and drunk." The Prophet (peace be upon him) said, "Then do not eat or drink for the rest of the day."