Allah says: O you who believe! Fasting has been prescribed for you as it was prescribed for those before you, so that you may become Muttaqoon (the pious). [Soorah al-Baqarah (2): 183] Fasting is a great act of worship, if it was not then Allah, the All Wise would not have made it obligatory on all nations. Abu Hurayrah (radhi allahu anhu) narrates: The Messenger of Allah (sallallahu alaihi wa-sallam) said: When the month of Ramadaan starts, the gates of Jannah (Paradise) are opened and the gates of Hell are closed, and Satans are chained. [Saheeh al-Bukharee vol: 3, no: 123 and Saheeh Muslim no: 2361 and 2362]
The gates of Jannah are opened as an encouragement for those who seek rewards from Allah and perform righteous deeds. Likewise, the gates of Hell are closed, since less sins are committed in this sacred month and the Shaytaan is chained in order to prevent him from misleading the people and attracting them to sinful acts.
Amongst the virtues of fastingis that it is an atonement of sins. Narrated Abu Hurayrah (radhi allahu anhu) that the Messenger of Allah (sallallahu alaihi wa-sallam) said: He who observed the fasts of the month of Ramadaan out of sincerity and hoping for the reward from Allah, he will have his past sins forgiven. [Saheeh al-Bukharee vol: 3, no: 125]
Abu Hurayrah (radhi allahu anhu) reported a Qudsi Hadeeth: Allah says: All the deeds of Adam's children belong to them, except fasting, which belongs to Me, and I will reward it. Fasting is a shield (against the Hell and sins). If one of you happens to be fasting then he should avoid +++ual relations with his wife, and should avoid quarreling. If someone quarrels with him, let him say: 'I am fasting.' By Him in Whose Hand is my soul, the smell of the mouth of a fasting person is better in the Sight of Allah than the musk. [Saheeh al-Bukharee (vol: 3, no: 118) and Saheeh Muslim (no: 2567)]
In this Hadeeth, Allah distinguished the sincere fast from all good deeds and He favored the fast to be greatly rewarded. Fasting is called a shield against Hell Fire because it protects the fasting person from shameful and unjust deeds, which in turn defend him from the Hell-Fire.
Fasting is a praiseworthy act, which carries two occasions of joy for the believer; one while he breaks his fast and enjoys the bounties of Allah, i.e. he was favored with the Mercy of Allah and granted the ability to fast and worship him, while others were deprived from this blessing. The second is when he will meet his Lord and enjoy the abundant rewards of fasting. Another virtue of fasting is its intercession on the Day of Judgement.
The Wisdom behind Fasting: