Laylat al-Qadr

Standing in prayer on the Night of Decree with faith forgives past sins.

Narrated by Abu Hurairah

Whoever stands (in prayer) on Laylat al-Qadr out of faith and hoping for reward, his past sins will be forgiven.

Sahih al-Bukhari 35, Sahih Muslim 760

What this hadith teaches

Laylat al-Qadr is in the last ten nights of Ramadan, most likely an odd night. Prayer on it is better than a thousand months.

Reference and grade

Grade
Sahih: agreed upon by al-Bukhari and Muslim
Narrator
Abu Hurairah

The hadith in Arabic نص الحديث

مَنْ يَقُمْ لَيْلَةَ الْقَدْرِ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ

Arabic text of Sahih al-Bukhari 35, as given on sunnah.com.