Belief
2/25. Chapter:
To establish the (Nawafil - voluntary) prayers on the night of Qadr is a part of faith
Sahih Bukhari
حَدَّثَنَا أَبُو الْيَمَانِ، قَالَ أَخْبَرَنَا شُعَيْبٌ، قَالَ حَدَّثَنَا أَبُو الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ يَقُمْ لَيْلَةَ الْقَدْرِ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ ".
Narrated Abu Huraira: Allah's Messenger (ﷺ) said, "Whoever establishes the prayers on the night of Qadr out of sincere faith and hoping to attain Allah's rewards (not to show off) then all his past sins will be forgiven."
Reference : Sahih al-Bukhari 35In-book reference : Book 2, Hadith 28USC-MSA web (English) reference : Vol. 1, Book 2, Hadith 35