Sahih MuslimChapter 6Hadith 1779
Full Sharh — Sahih Muslim 1779
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنْ قَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ " .
English Translation
Abu Huraira reported Allah's Messenger (ﷺ) as saying:He who observed prayer at night during Ramadan, because of faith and seeking his reward from Allah, his previous sins would be forgiven
Source
Sahih Muslim(صحيح مسلم)
The Book of Prayer - Travellers
Hadith Number
1779