Reported on the authority of Sahl bin Sa'ad that the Prophet said, "Jannah has an entrance by the name of Ar-Rayyaan which is exclusively reserved for the fasting individuals. On the Day of Judgment, they will be called to pass through this entrance, after which it will be closed behind them and no one else will be allowed to use it."

It should be known that there are three grades of fasting:

Ordinary fasting. Abstaining from food, drink and sexual satisfaction.

Special fasting. Keeping one's ears, eyes, tongue, hands and feet-and all other organs-free from sin.

Extra-special fasting. Fasting of the heart from unworthy concerns and worldly thoughts, in total disregard of everything but Allah.

See not what displeases Allah:

A chaste regard, restrained from viewing anything that is blameworthy or reprehensible, or which distracts the heart and diverts it from the remembrance of God. The Prophet, said: "The furtive (secret) glance is one of the poisoned arrows of Satan, on him be God's curse. Whoever forsakes it for fear of God, will receive from Him, Great and Gracious is He, a faith the sweetness of which he will find within his heart."

Jabir relates from Anas that God's Messenger, on him be peace, said: "Five things break a man's fast: lying, backbiting, scandal mongering, perjury and a lustful gaze."

Speak no evil:

Guarding one's tongue from twaddle, lying, backbiting, scandal mongering, obscenity, rudeness, wrangling and controversy; making it observe silence and occupying it with remembrance of Allah and with recitation of the Quran. This is the fasting of the tongue. Sufyan said: "backbiting vitiates the fast." Layth quotes Mujahid as saying: "Two habits vitiate fasting: backbiting and telling lies."

The Prophet said: "Fasting is a shield; so when one of you is fasting he should not use foul or foolish talk. If someone attacks him or insults him, let him say: 'I am fasting, I am fasting!' "

Hear no evil:

Closing one's ears to everything reprehensible; for everything unlawful to utter is likewise unlawful to listen to. That is why Allah equated the eavesdropper with the profiteer " (They like to) listen to falsehood, to devour anything forbidden" (Quran 5: 42).

Do not:

Keeping all other limbs and organs away from sin: the hands and feet from reprehensible deeds, and the stomach from questionable food at the time for breaking Fast. It is meaningless to Fast -- to abstain from lawful food - only to break one's Fast on what is unlawful. A man who Fast like this may be compared to one who builds a castle but demolishes a city. Lawful food injurious in quantity not in quality, so Fasting is to reduce the former. A person might well give up excessive use of medicine, from fear of ill effects, but he would be a fool to switch to taking poison. The unlawful is a poison deadly to religion, while the lawful is a medicine, beneficial in small doses but harmful in excess. The object of Fasting is to induce moderation. Said the Prophet, on him be peace: 'How many of those who Fast get nothing from it but hunger and thirst!' This has been taken to mean those who break their Fast on unlawful food. Some say it refers to those who abstain from lawful food, but break their Fast on human flesh through backbiting, which is unlawful. Others consider it an allusion to those who do not guard their organs from sin.

Avoid overeating:

Not to over-indulge in lawful food at the time of breaking Fast, to the point of stuffing one's belly. There is no receptacle more odious to God, Great and Glorious is He, than a belly stuffed full with lawful food. Of what use is the Fast as a means of conquering God's enemy and abating appetite, if at the time of breaking it one not only makes up for all one has missed during the daytime, but perhaps also indulges in a variety of extra foods? It has even become the custom to stock up for Ramadan with all kinds of foodstuffs, so that more is consumed during that time than in the course of several other months put together. It is well known that the object of Fasting is to experience hunger and to check desire, in order to reinforce the soul in piety. If the stomach is starved from early morning till evening, so that its appetite is aroused and its craving intensified, and it is then offered delicacies and allowed to eat its fill, its taste for pleasure is increased and its force exaggerated; passions are activated which would have lain dormant under normal conditions.

The spirit and secret nature of Fasting is to weaken the forces which are Satan's means of leading us back to evil. It is therefore essential to cut down one's intake to what one would consume on a normal night, when not Fasting. No benefit is derived from the Fast if one consumes as much as one would usually take during the day and night combined. Moreover, one of the properties consists in taking little sleep during the daytime, so that one feels the hunger and thirst and becomes conscious of the weakening of one's powers, with the consequent purification of the heart.

One should let a certain degree of weakness carry over into the night, making it easier to perform the night Prayers (tahajjud) and to recite the praises (awrad). It may then be that Satan will not hover around one's heart, and that one will behold the Kingdom of Heaven. The Night of Destiny represents the night on which something of this Kingdom is revealed. This is what is meant by the words of God, Exalted is He:

'We surely revealed it on the Night of Power.' [Quran 97:1]

Anyone who puts a bag of food between his heart and his breast becomes blind to this revelation. Nor is keeping the stomach empty sufficient to remove the veil, unless one also empties the mind of everything but God, Great and Glorious is He. That is the entire matter, and the starting point of it all is cutting down on food.

(Excerpt from "Inner Dimensions of Islamic Worship", a compilation of Imam Abu Hamid Al-Ghazali's works)