Narrated by Ibn Umar (Radhiallaho anhuma):
I heard Allah’s Messenger (sallallaahu ‘alaihi wasallam) 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.”
Sahih Al-Bukhari Vol. 3 : No. 124
Devils are chained in The month of Ramadan
Narrated by Abu Huraira (Radhiallaho anho):
Allah’s Messenger (sallallaahu ‘alaihi 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.”
Sahih Al-Bukhari Vol. 3 : No. 122
The virtues of Ramadan
Narrated by Abu Huraira (Radhiallaho anho):
Allah’s Messenger (sallallaahu ‘alaihi wasallam) said “The blessed month has come to you. Allah has made fasting during it obligatory upon you. During it, the gates to Paradise are opened and the gates to hellfire are locked, and the devils are chained. There is a night [during this month] which is better than a thousand months. Whoever is deprived of its good is really deprived [of
something great].”
This is related to Ahmad, an-Nasa’i, and al-Baihaqi.
Gates of Paradise for women
Narrated by Anas ibn Malik (Radhiallaho anho):
Allah’s Messenger (sallallaahu ‘alaihi wasallam) said, “When a woman observes the five times of prayer, fasts during Ramadan, preserves her chastity, and obeys her husband, she may enter by any of the gates of Paradise she wishes.”
(Al-Tirmidhi 956, Abu Nu’aym transmitted it in al-Hilyah)