What was the Prophet Muhammad's (saw) reaction when al-Ash'ath b. Qais invited him to join him for lunch on the day of 'Ashura?
 Qais b Sakan reported that al-Ash'ath b. Qais went to 'Abdullah on the day of 'Ashura while he was eating. He said:                      Abu Muhammad, come near and dine. Upon this he said: I am fasting. Thereupon he said: We used to observe fast and then (this practice) was abandoned.