The following incident has been narrated by al-Saduq on pp. 84-85 of his Al-Amali thus:
Muhammad ibn Ibrahim says that Ahmed ibn Muhammad-al- Hamadani says that Ali ibn al-Hassan ibn Fadal quotes his father quoting al-Hassan's father Imam Ali bin Musa al-Rida (as) who in turn quotes his father Imam Musa ibn Ja'fer (as) quoting his father the master of martyrs Imam al-Husain ibn Ali ibn Abu Talib (as) saying that the Messenger of Allah (pbuh) delivered a sermon once in which he said:
O people! A month has approached you laden with blessing, mercy and forgiveness; it is a month which Allah regards as the best of all months. Its days, in the sight of Allah, are the best of days; its nights are the best of nights; its hours are the best of hours. It is a month in which you are invited to be the guests of Allah, and you are regarded during it as worthy of enjoying Allah's Grace. Your breathing in it praises the Almighty, and your sleeping adores Him. Your voluntary acts of worship are accepted, and your pleas are answered. Ask Allah your Lord, therefore, in sincere intentions and pure hearts to enable you to fast during it and to recite His Book, for only a wretch is the one who is deprived of Allah's forgiveness during this great month. And let your hunger and thirst during it remind you of the hunger and thirst of the Day of Resurrection. Give alms to the poor and indigent among you; surround your elderly with respect, and be kind to your youngsters. Visit your kin and safeguard your tongues, and do not look at what Allah has prohibited you from seeing, and do not listen to anything your ears are forbidden to hear. Be kind to the orphans of others so that your own orphans will equally receive kindness. Repent your sins to Allah and raise your hands to Him in supplica- tion during the times of your prayers, for they are the best times during which the Almighty looks with mercy to His servants and answers their pleas when they plead to Him. O people! Your souls are pawned by your deeds; therefore, release them by seeking Allah's forgiveness. Your backs are over-burdened by the weight of your sins; therefore, lighten their burden by prolonging your prostration. Be informed that the Exalted and Almighty has sworn by His Dignity not to torture those who perform their prayers and prostrate to Him, and not to terrify them by the sight of the fire when people are resurrected for judgment. O people! Whoever among you provides iftar to a believer during this month will receive a reward equal to one who sets a slave free, and all his past sins will be forgiven.
Having said so, people said to him: "O Messenger of Allah! Not all of us can do that!" He (pbuh), thereupon, responded by saying,
Shun the fire of hell even by half a date! Shun the fire of hell even by a drink of water! O People! Whoever among you improves his conduct during this month will have a safe passage on al-Sirat al-Mustaqeem, (the straight path) when many feet will slip away, and whoever among you decreases the burdens of his slave (or anyone who works for him) will be rewarded by Allah decreasing his reckoning. Whoever among you abstains from harming others will be spared the Wrath of the Almighty when he meets Him. Whoever among you affords generosity to an orphan will be rewarded by Allah being generous to him on the Day of Judgment. Whoever among you improves the ties with his kin will be rewarded by Allah including him in His mercy, and whoever among you severs his ties with his kin, Allah will withhold His mercy from him upon meeting Him. Whoever among you offers voluntary prayers, Allah will decree a clearance for him from the torment of the fire. Whoever among you performs an obligation will receive the reward of one who has performed seventy obligations in other months. Whoever among you increases the sending of blessings unto me, Allah will make the balance of his good deeds weigh heavily when scales will be light. Whoever among you recites one verse of the Holy Qur'an will receive the blessing of one who recites the entire Holy Qur'an in another month. O people! The gates of heaven in this month are kept open; so, pray Allah your Lord not to close them against you, and the gates of the fire are kept closed; so, pray Allah your Lord not to open them for you; and the devils are kept chained; therefore, pray Allah your Lord not to unleash them against you.
Advising the great sahabi Abu Tharr al-Ghifari, may Allah be pleased vvith him, regarding the fast being a protection against the fire, he (pbuh) is quoted saying, "Shall I inform you of a deed which, if you do it, will keep Satan away from you as much as the distance between the east of the earth and the west?" People answered, "O yes, indeed, O Messenger of Allah!" He (pbuh) said, "Fast darkens his (Satan's) face; alms break his back; the desire to please Allah and the giving of assistance to do good deeds cut his tail off, and seeking Allah's forgiveness cuts off his aorta." Then he added, "For everything there is a purification (zakat), and the purification of bodies is the fast." He (pbuh) is also quoted saying, "One who fasts is considered to be adoring his Creator even while sleeping on his bed as long as he does not backbite any Muslim." He (pbuh) has also said, 'There are two merry occasions for anyone who performs the fast: one when he breaks his fast, and one when he meets his Lord, the Exalted, the Almighty. I swear by the One Who controls Muhammad's life, the excess on the mouth of one who fasts is better in the sight of Allah than the sweet smell of musk." He (pbuh) has also said that the Exalted and Almighty has said (in a Qudsi hadith) that all good deeds of a descendant of Adam are His (to reward) "except the fast, for it is mine, and I shall reward for it. All good deeds of the son of Adam are rewarded with ten to seven hundred times except perseverance, for it is mine and I reward for it." So, the knowledge of the rewards of perseverance is with Allah, and "perseverance" means fast.
Regarding the interpretation of His saying (in the Holy Qur'an) "... and seek aid with perseverance," meaning the fast, it is reported that the person who fasts enjoys the gardens of Paradise and the angels keep praying for him till he breaks his fast. If a believer stands during a portion of the night to perform additional optional prayers, then he wakes up fasting, no sin will be recorded against him. Whenever he takes one step, it will be recorded as a good deed for him, and if he dies during daytime, his soul will ascend the heights of heaven. If he lives to break his fast, the Almighty will consider him among those who often return to Him for forgiveness. In the book titled Thawab al-A'mal, relying on the authority of Abu Abdullah who quotes his forefathers, peace be upon all of them, the author, namely Shaikh al-Qummi al-Saduq, quotes one tradition indicating that the Messenger of Allah (pbuh) has said, "The sleep of someone fasting is like adoration, and his breath praises the Almighty."