Sayyiduna Abdullah bin Umar (may Allah be pleased with him) says: The people of the Age of Ignorance used to fast on the Day of Ashura, but when the command for the obligation of the month of Ramadan was revealed, the Messenger of Allah (peace and blessings be upon him) was asked about this fast. He (peace and blessings be upon him) said: This is one of the days of Allah; whoever wishes may fast on it, and whoever wishes may leave it.