Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said, "When Ramadan begins, the gates of Jannah are opened, the gates of Hell are closed, and the devils are chained.''
[Al-Bukhari and Muslim]
Commentary:
This is a special distinction of the month of Ramadan during which Muslims become more inclined towards the worship of Allah. They pay greater attention to the recitation of the Qur'an, remembrance of Allah, worship, and seeking pardon for sins.
Riyad-us-Saliheen – Hadith No :1220