It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) said: 'There has come to you Ramadan, a blessed month, which Allah, the Mighty and Sublime, has enjoined you to fast. In it the gates of heavens are opened and the gates of Hell are closed, and every devil is chained up. In it Allah has a night which is better than a thousand months; whoever is deprived of its goodness is indeed deprived."'
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا بِشْرُ بْنُ هِلاَلٍ، قَالَ حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ أَيُّوبَ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَتَاكُمْ رَمَضَانُ شَهْرٌ مُبَارَكٌ فَرَضَ اللَّهُ عَزَّ وَجَلَّ عَلَيْكُمْ صِيَامَهُ تُفْتَحُ فِيهِ أَبْوَابُ السَّمَاءِ وَتُغْلَقُ فِيهِ أَبْوَابُ الْجَحِيمِ وَتُغَلُّ فِيهِ مَرَدَةُ الشَّيَاطِينِ لِلَّهِ فِيهِ لَيْلَةٌ خَيْرٌ مِنْ أَلْفِ شَهْرٍ مَنْ حُرِمَ خَيْرَهَا فَقَدْ حُرِمَ " .
sunnah.com