Sayyiduna Muhammad bin Saifi Ansari (may Allah be pleased with him) narrates: On the day of Ashura, the Noble Prophet (peace and blessings be upon him) came to us. He inquired: Has anyone among you eaten anything today? The people replied: Some of us have eaten something and some have not eaten anything. The Noble Prophet (peace and blessings be upon him) said: Whoever among you has not eaten anything should observe the fast, and whoever has eaten something, then he should complete the rest of the day (as a fast), and inform the people of the surrounding areas that they should also complete the rest of the day (i.e., not eat anything).