Muhammad ibn Yaqub, from a group of our companions, from Ahmad ibn Muhammad ibn Isa, from Hamzah ibn Yala, from Muhammad ibn al-Hasan ibn Abi Khalid, raising it from Abu Abdillah عليه السلام, peace be upon him: Imam عليه السلام said: “When the crescent of Rajab is confirmed, then count fifty-nine days, and fast on the sixtieth day.”