Sahih Muslim 760 b
Abu Huraira reported Allah's Apostle (ﷺ) as saying:
He who prayed on the Lailat-ul-Qadr (the Majestic Night) knowing that it is (the same night). I (believe) that he (the Prophet also) said: (He who does) it with faith and seeking reward (from Allah), his sins would be forgiven.
حَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا شَبَابَةُ، حَدَّثَنِي وَرْقَاءُ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏
"‏ مَنْ يَقُمْ لَيْلَةَ الْقَدْرِ فَيُوَافِقُهَا - أُرَاهُ قَالَ - إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ ‏"‏ ‏.‏