The Book of Fasting
22/39. Chapter:
The Reward of one who prays Qiyam in Ramadan and fasts the month out of faith and hope for reward
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ جَبَلَةَ، قَالَ حَدَّثَنَا الْمُعَافَى، قَالَ حَدَّثَنَا مُوسَى، عَنْ إِسْحَاقَ بْنِ رَاشِدٍ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم أَخْبَرَتْهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُرَغِّبُ النَّاسَ فِي قِيَامِ رَمَضَانَ مِنْ غَيْرِ أَنْ يَأْمُرَهُمْ بِعَزِيمَةِ أَمْرٍ فِيهِ فَيَقُولُ " مَنْ قَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ " .
'Urwah bin Az-Zubair narrated that Aishah told him that: the Messenger of Allah used to encourage the people to pray Qiyam in Ramadan, without insisting on that. He said: "Whoever spends the nights of Ramadan in prayer out of faith and in the hope of reward, he will be forgiven his previous sins." '
Reference : Sunan an-Nasa'i 2192In-book reference : Book 22, Hadith 103English translation : Vol. 3, Book 22, Hadith 2194