Abu Hurairah reported the Messenger of Allah, upon whom be peace, saying: “Allah said: ‘Every action of the son of Adam is for him except fasting, for that is solely for Me. I give the reward for it.’ The fast is a shield. If one is fasting, he should not use foul language, raise his voice, or behave foolishly. If someone reviles him or fights with him he should say, ‘I am fasting,’ twice. By the One in whose hand is the soul of Muhammad, the [bad] breath of the one who is fasting is better in the sight of Allah on the Day of Resurrection than the smell of musk. The one who is fasting is happy at two times: when he breaks his fast he is happy with it, and when he meets his Lord he will be happy that he has fasted.” This is related by Ahmad, Muslim, and an-Nasa’i. A similar version was recorded by al-Bukhari and Abu Dawud, but with the following addition: “He leaves his food, drink, and desires for My sake. His fasting is for Me… I will give the reward for it, and for every good deed, he will receive ten similar to it.”
‘Abdullah ibn ‘Amr reported that the Messenger of Allah, upon whom be peace, said: “The fast and the Qur’an are two intercessors for the servant of Allah on the Day of Resurrection. The fast will say: ‘O Lord, I prevented him from his food and desires during the day. Let me intercede for him.’ The Qur’an will say: ‘I prevented him from sleeping at night. Let me intercede for him.’ And their intercession will be accepted.” Ahmad related this hadith with a sahih chain.
Abu Umamah reported: “I came to the Messenger of Allah and said: ‘Order me to do a deed that will allow me to enter Paradise.’ He said: ‘Stick to fasting, as there is no equivalent to it.’ Then I came to him again and he said: ‘Stick to fasting.”‘ This hadith is related by Ahmad, an-Nasa’i, and al-Hakim who classified it as sahih.
Abu Sa’id al-Khudri reported that the Messenger of Allah said: “No servant fasts on a day in the path of Allah except that Allah removes the hellfire seventy years further away from his face.” This is related by “the group,” except for Abu Dawud.
Sahl ibn Sa’d reported that the Prophet said: “There is a gate to Paradise that is called ar-Rayyan. On the Day of Resurrection it will say: ‘Where are those who fasted?’ When the last [one] has passed through the gate, it will be locked.” This is related by alBukhari and Muslim.