(1) باب فَضْلِ لَيْلَةِ الْقَدْرِ
Narrated Abu Huraira:
The Prophet (ﷺ) said, "Whoever fasted the month of Ramadan out of sincere Faith (i.e. belief) and hoping for a reward from Allah, then all his past sins will be forgiven, and whoever stood for the prayers in the night of Qadr out of sincere Faith and hoping for a reward from Allah, then all his previous sins will be forgiven ."
Reference: Sahih al-Bukhari 2014
In-book reference: Book 32, Hadith 1
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 32, Hadith 231