It is narrated from Hazrat Rabi’ (may Allah be pleased with her) that once, on the day of Ashura (the 10th of Muharram), the Prophet (peace and blessings be upon him) sent a messenger to the settlements of the Ansar and had it announced that whoever among you is fasting today should complete his fast, and whoever has already eaten or drunk something should spend the rest of the day without eating or drinking.