Musannaf Ibn Abi Shaybah 9602 — Fasting the day of Ashura

Sayyiduna Muhammad bin Sayfi (may Allah be pleased with him) said: On the day of Ashura the Messenger of Allah (peace and blessings be upon him) said to us: "Is there anyone among you who has eaten today?" We said: "Some of us have eaten and some of us have not eaten." The Prophet (peace and blessings be upon him) said: "Complete the rest of your day, both those who have eaten and those who have not eaten. And send word to the people living on the outskirts of Madinah too, that they should complete the rest of their day."