Mishkat al-Masabih #1871

Abu Huraira reported God’s messenger as saying, “Ramadan, a blessed month, has come to you during which God has made it obligatory for you to fast. In it the gates of heaven are opened, the gates of al-Jahim are locked, and the rebellious devils are chained. In it God has a night which is better than a thousand months. He who is deprived of its good has indeed suffered deprivation." Ahmad and Nasa’i transmitted it.