Sunan an-Nasa'i 1603
سنن النسائي#1603Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ إِسْمَاعِيلَ أَبُو بَكْرٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ أَسْمَاءَ، قَالَ حَدَّثَنَا جُوَيْرِيَةُ، عَنْ مَالِكٍ، قَالَ قَالَ الزُّهْرِيُّ أَخْبَرَنِي أَبُو سَلَمَةَ بْنُ عَبْدِ الرَّحْمَنِ، وَحُمَيْدُ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنْ قَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ " .
It was narrated from Abu Hurairah that:The Messenger of Allah (ﷺ) said: "Whoever prays Qiyam during Ramadan out of faith and in the hope of reward, he will be forgiven his previous sins
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 20:6