Hadith 1898
Narrated Abu Huraira: Allah's Apostle said, "When Ramadan begins, the gates of Paradise are opened."
Hadith 1899
Narrated Abu Huraira: Allah's Apostle 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."
Hadith 1900
Narrated Ibn `Umar: I heard Allah's Apostle saying, "When you see the crescent (of the month of Ramadan), start fasting, and when you see the crescent (of the month of Shawwal), stop fasting; and if the sky is overcast (and you can't see it) then regard the month of Ramadan as of 30 days."