Chapter on Voluntary Fasting and Its Rewards on Different Days

It is narrated by al-Hasan ibn Rashid from Abu Abdullah (Imam Jafar ibn Muhammad Al-Sadiq عليه السلام), who said: I said: 'May I be your ransom, is there a festival for Muslims other than the two Eids?' Imam عليه السلام said: 'Yes, O’ Hasan, and it is greater and more noble than them.' I said: 'What day is it?' Imam عليه السلام said: 'It is the day on which Amir al-Mu'minin عليه السلام was appointed as a guide for the people.' I said: 'May I be your ransom, which day is that?' Imam عليه السلام said: 'The days revolve, and it is the 18th of Dhu al-Hijjah.' I said: 'May I be your ransom, what should we do on that day?' Imam عليه السلام said: 'You should fast it, O’ Hasan, and increase your prayers upon Muhammad and his family عليه السلام. You should also declare your disassociation to Allah سبحانه وتعالى, the Almighty, from those who wronged them and usurped their rights. Indeed, the Prophets عليه السلام used to command their successors to designate the day on which the successor was appointed as a festival.' I said: 'What is the reward for fasting it for us?' Imam عليه السلام said: 'The reward of fasting sixty months. Also, do not neglect fasting on the 27th of Rajab, for it is the day on which prophethood was bestowed upon Muhammad صلى الله عليه وعلى آله وسلم (peace and blessings be upon him and his family), and its reward for you is like fasting sixty months.'"