Narrated Sahl (Radi-Allahu 'anhu):
The Prophet (Sallallahu 'Alaihi Wa Sallam) said, "There is a gate inParadise called Ar-Raiyan, and those who observe fasts will enter throughit 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 getup, and none except them will enter through it. After their entry the gatewill be closed and nobody will enter through it."
Bukhari Vol. 3 : No. 120