It is narrated from Sayyiduna Salamah bin Akwa’ (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) ordered a man from the tribe of Aslam on the day of ‘Ashura to announce among the people that whoever is fasting today should complete his fast, and whoever has eaten or drunk something should not eat or drink anything further and should complete the fast until the end of its time.