It was narrated that Humaid bin ‘Abdur-Rahman bin ‘Awf said: “I heard Muawiyah say on the day of ‘Ashura’ when he was on the Minbar: people of Al-Madinah, where are your scholars? I heard the Messenger of Allah ﷺ say on this day: “I am fasting, so whoever wants to fast let him do so.” (Sahih)