It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that once the Noble Prophet (peace and blessings be upon him) passed by some Jews who were observing the fast of Ashura. The Noble Prophet (peace and blessings be upon him) asked them, "What is this fast?" They replied, "On this day, Allah saved Hazrat Musa (peace be upon him) and the Children of Israel from drowning and drowned Pharaoh. On this same day, the ark of Hazrat Nuh (peace be upon him) came to rest on Mount Judi. So Hazrat Nuh and Musa (peace be upon them) fasted on this day to thank Allah." The Noble Prophet (peace and blessings be upon him) said, "I have more right to Musa than you, and I am more deserving of fasting on this day." Thus, the Noble Prophet (peace and blessings be upon him) instructed his companions to fast on this day.