'A'isha (Allah be pleased with her) reported that the Quraish used to observe fast on the day of Ashura during the pre-Islamic days. The Messenger of Allah (ﷺ) then commanded to fast on that day till (fasting) in Ramadan became obligatory. Then the Messenger of Allah (ﷺ) said: He who wished to fast should do so, and he who wished to break it may do so.