It is related by Abu Hurairah (RAA) that the Apostle of God (sallallaho alaihi wa sallam) said “When the month of Ramadhan comes, the Gates of Heaven are thrown open and the Gates of Hell are shut, and the devils are put behind bars” In another report, the “Gates of Mercy” are mentioned in place of the “Gates of Heaven”. [Bukhari and Muslim]
Commentary – Commenting of this Tradition, Shah Wali-ullah remarks that as the devout bondsmen apply themselves to worship and good-doings during the month of Ramadhan and spend their days in God- remembrance and recitation of the Qur’an while Fasting, and a major part of their nights in Taraweeh and Tahajjud, supplication and repentance, under the influence of their high spirituality and devotional exertions the hearts of the common Muslims, too become more inclined towards prayer and piety and they, on the whole succeed in abstaining from good many sins. Owing to the generation of the atmosphere worship and virtue in the Islamic circles, people who are not wholly disregardful of transcendental truths develop a fondness for things that are pleasing to God and an aversion for acts that are repugnant to Him. moreover, in this blessed month the recompense on even smaller acts of moral goodness is made much greater by God than on other days. In consequence of all this, the gates of Paradise are opened and of Hell are closed for such people and the devils are not left free to tempt and mislead them.