Islamic calendar – Q4
When the Prophet ﷺ arrived in Medina, he found the Jews fasting on the day of Ashura. He asked why, and they replied that it is the day when Allah saved Moses and the Children of Israel from Pharaoh. The Prophet ﷺ said that we have more right to Moses than they do. He therefore fasted that day and ordered that the fast be observed. (Reported by al-Bukhari, 2004)