عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((مَنْ قَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ))
Narrated by Sayyiduna Abu Hurairah (may Allah be pleased with him): The Messenger of Allah (peace and blessings be upon him and his family) said: Whoever stands (in prayer) during the nights of Ramadan with faith and seeking reward, his previous sins will be forgiven.