[Sahih Bukhari : volume 3, Book 31, Number 118]

Narrated Abu Huraira (Radi Allah Anhu): Allah’s Apostle (sal-allahu-alleihi-wasallam) said, “Fasting is a shield (or a screen or a shelter). So, the person observing fasting should avoid sexual relation with his wife and should not behave foolishly and impudently, and if somebody fights with him or abuses him, he should tell him twice, ‘I am fasting.” The Prophet added, “By Him in Whose Hands my soul is, the smell coming out from the mouth of a fasting person is better in the sight of Allah than the smell of musk. (Allah says about the fasting person), ‘He has left his food, drink and desires for My sake. The fast is for Me. So I will reward (the fasting person) for it and the reward of good deeds is multiplied ten times.”

[Sahih Bukhari : volume 3, Book 31, Number 120]

Narrated Sahl (Radi Allah Anhu): The Prophet Muhammad (sal-allahu-alleihi-wasallam) said, “There is a gate in Paradise called Ar-Raiyan, and those who observe fasts will enter through it on the Day of Resurrection and none except them will enter through it. It will be said, ‘Where are those who used to observe fasts?’ They will get up, and none except them will enter through it. After their entry the gate will be closed and nobody will enter through it.”

[Sahih Bukhari : volume 3, Book 31, Number 122]

Narrated Abu Huraira (Radi Allah Anhu): Allah’s Apostle (sal-allahu-alleihi-wasallam) said, “When Ramadan begins, the gates of Paradise are opened.”

[Sahih Bukhari : volume 3, Book 31, Number 123]

Narrated Abu Huraira (Radi Allah Anhu): Allah’s Apostle (sal-allahu-alleihi-wasallam) said, “When the month of Ramadan starts, the gates of the heaven are opened and the gates of Hell are closed and the devils are chained.”

Source: http://sunniyat.wordpress.com/2010/08/30/ramazan-rewards-for-those-who-fasts/