Al-Husayn ibn Said, from Fadalah ibn Ayyub, from Dawud ibn Farqad, from his father, who said: Hafs al-Awar wrote to me: “Ask Abu Abdillah عليه السلام, peace be upon him, about three matters.” So Abu Abdillah عليه السلام, peace be upon him, said: “What are they?” He (narrator) said: “One who abandoned fasting three days in a month.” Abu Abdillah عليه السلام, peace be upon him, said: “Due to illness, or old age, or thirst?” He (narrator) replied: “Then explain to me each matter separately.” Imam عليه السلام said: “If it was due to illness, then when he recovers, let him make it up (the fasts). And if it was due to old age or thirst, then in place of each day is one mudd.”