It is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "When the month of Ramadan comes, the gates of the heavens are opened, the gates of Hell are closed, and the devils are chained."
In this hadith it is stated: "The gates of the heavens are opened." In Musnad Ahmad it is stated: "The gates of Paradise are opened." The mention of the gates of Paradise, Hell, and the heavens is a reality, not a metaphor. And the opening of the gates of Paradise or the heavens is a glad tiding for those who fast, and the closing of the gates of Hell is good news for them. The purpose of this is to encourage the believers towards righteous deeds and to make full use of the bounties and blessings of the blessed month of Ramadan. And the believer who, with tawhid (monotheism), sincerity, and righteous deeds, passes away in this noble month, he will, by Allah’s mercy and grace, be deserving of Paradise through these opened gates, and for him the gates of Hell will be closed. This is not for the disbeliever, hypocrite, sinner, or criminal. The meaning of the devils being chained and shackled is that, unlike in other months, they are not able to overpower the average Muslim in Ramadan. That is why it is observed that in Ramadan, the number of those who perform prayers, recite (the Qur’an), perform Tarawih, give charity and alms, and do righteous deeds increases.