Sayyiduna Asma bin Haritha (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) sent him to his people and instructed: Guide those people to fast on this day. I asked: If I find them in a state that they have already eaten something, then the Prophet Muhammad (peace and blessings be upon him) said: They should complete the fast till the end of the day (i.e., they should not eat anything further).