It is mandatory to abstain from food and drink from dawn until sunset Ramadan

 In the month of Ramadan, it is mandatory to abstain from food and drink from dawn until sunset.

Talha bin 'Ubaidullah narrated the following:

Bedouin with untidy hair approached Muhammad, the Messenger of Allah, and said, "O Muhammad, the Messenger of Allah! Please inform me of any requirements that Allah has imposed upon me in reference to the prayers. He responded by saying, 

"If you want to pray Nawafil, you have to perform the five obligatory prayers within a day and night (24 hours) without making a single mistake."

 The Bedouin continued by asking, "Inform me what Allah has made compulsory for me in regards to the fasting." As a response, he stated, "You are required to fast throughout the entire month of Ramadan, unless you want to fast more as Nawafil." The Bedouin continued their line of questioning by requesting, "Tell me how much Zakat Allah has enjoined on me." As a result, Allah's Messenger ( PBUH) shared with him all of the guidelines (also known as the foundations) of Islam. The Bedouin then responded, "By Him Who has honored you, I will neither perform any Nawafil nor will I decrease what Allah has enjoined on me. I will not do either of these things." The Messenger of Allah (may Allah be pleased with him) once stated, "If he is saying the truth, he will succeed (or he will be granted Paradise)."

Ibn 'Umar said that the Prophet (peace be upon him) kept the fast on the 10th of Muharram ('Ashura), and he commanded (Muslims) to fast on that day; but, when the fasting of the month of Ramadan was required, the fasting of the 'Ashura' was abandoned. 'Ashura' is the 10th day of the Islamic month of Muharram. "Abdullah did not fast on that day unless, by some stroke of luck, it happened to coincide with his regular fasting."

In the time before Islam, members of (the tribe of) Quraish would observe a fast on the day of Ashura. Subsequently, Allah's Apostle commanded Muslims to observe a fast on this day until the fasting that takes place during the month of Ramadan was mandated. In response, the Prophet (peace be upon him) said, "He who wants to fast (on 'Ashura') may fast, and he who does not want to fast may not fast."

(2)The advantages of As-Saum (the fasting)

According to Abu Huraira, the Messenger of Allah (PBUH) was quoted as saying, "Fasting is a shield (or a screen or a shelter)." Therefore, a person who is fasting should abstain from having sexual relations with his wife, should not behave stupidly or impudently, and should remind anybody who clashes with him or abuses him twice that 

"I am fasting." The Prophet (peace be upon him) continued by saying, "By Him in Whose Hands my soul is, the smell that comes out of the mouth of a person who is fasting is better in the sight of Allah than the smell of musk."

 (Allah is quoted as saying this of the individual who is fasting) "He has forsaken Me his food, his drink, and his desires." This fast is for the sake of Me. Therefore, I will reward (the one who is fasting) for it, and the prize for doing good actions will be increased by 10."

(3)This chapter explains that the fasting is an expiation for sins. 

From Hudhaifa, Abu Wail related the following:

'Umar questioned the people, "Who among you remembers the narration of the Prophet (PBUH) about the ailment?" Hudhaifa reported, "I overheard the Prophet (peace be upon him) saying, 'The affliction of a person in his property, family, and neighbors is expiated by his prayers, fasting, and giving in charity.'" 'Umar responded by saying, "I do not ask about that; rather, I ask about those afflictions which will spread like the waves of the sea." 

Hudhaifa responded by saying, "There is a closed gate in front of those afflictions." Umar said, "Will that gate be opened, or will it be broken?" The response he gave was, "It will be broken." 'Umar was quoted as saying, "Then the gate will not be closed again until the Day of Resurrection." We asked Masruq, "Would you ask Hudhaifa whether or not 'Umar knew what that gate symbolized?" Masruq responded that he would. When he asked him, the other person responded, "He (Umar) knew it as surely as one knows that there will be night before there is morning tomorrow."

(4) Ar-Raiyan is for those who are observing:

As Sahl related it:

The Prophet stated (PBUH), "There is a gate in Paradise called Ar-Raiyan, and on the Day of Resurrection, those who observe fasts will enter through it, and nobody else will enter through it except for them." People will ask, "Where are those who used to observe fasts?" in response to this. They will stand up, and no one other than themselves will go through that entrance. Once they have passed through, the gate will be locked and nobody will be able to access the area via it." 'Abu Huraira related the following:

"Whoever gives two kinds (of things or property) in charity for the Cause of Allah, will be called from the gates of Paradise, and will be addressed, 'O slaves of Allah!'" said the Messenger of Allah (PBUH). This is the place to find success.' So whoever was among the people who used to say their prayers will be called from the gate of the prayer; and whoever was among the people who used to take part in Jihad will be called from the gate of Jihad; and whoever was among those who used to observe fasts will be called from the gate of Ar-Raiyan; and whoever was among those who used to give in charity will be called from the gate of charity." 

Abu Bakr exclaimed, "O Messenger of Allah (PBUH), let my parents be killed as a sacrifice for you!" He who is summoned from those gates will not experience any difficulty or necessity in his life. Will there be someone who will be summoned from each and every one of these gates? The Prophet (peace be upon him) responded by saying, "Yes, and I hope that you will be one of them."