the Messenger of Allah said: "On the first night of the month of Ramadan, the Shayatin are shackled, the jinns are restrained, the gates of the Fires are shut such that no gate among them would be opened. The gates of Paradise are opened such that no gate among them would be closed, and a caller calls: 'O seeker of the good; come near!' and 'O seeker of evil; stop! For there are those whom Allah frees from the Fire.' And that is every night."  

رَسُولُ اللَّهِ ﷺ إِذَا كَانَ أَوَّلُ لَيْلَةٍ مِنْ شَهْرِ رَمَضَانَ صُفِّدَتِ الشَّيَاطِينُ وَمَرَدَةُ الْجِنِّ وَغُلِّقَتْ أَبْوَابُ النَّارِ فَلَمْ يُفْتَحْ مِنْهَا بَابٌ وَفُتِّحَتْ أَبْوَابُ الْجَنَّةِ فَلَمْ يُغْلَقْ مِنْهَا بَابٌ وَيُنَادِي مُنَادٍ يَا بَاغِيَ الْخَيْرِ أَقْبِلْ وَيَا بَاغِيَ الشَّرِّ أَقْصِرْ وَلِلَّهِ عُتَقَاءُ مِنَ النَّارِ وَذَلِكَ كُلَّ لَيْلَةٍ قَالَ وَفِي الْبَابِ عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ وَابْنِ مَسْعُودٍ وَسَلْمَانَ  

the Messenger of Allah said: "Whoever fasts Ramadan and stands (in the night prayer) for it out of faith and seeking a reward (from Allah), he will be forgiven what preceded of his sins. Whoever stands (in the night prayer) on the Night of Al-Qadr out of faith and seeking a reward (from Allah), he will be forgiven what preceded of his sins."  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ صَامَ رَمَضَانَ وَقَامَهُ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ وَمَنْ قَامَ لَيْلَةَ الْقَدْرِ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ هَذَا حَدِيثٌ صَحِيحٌ