Sahih al-Bukhari 526
Sahih al-Bukhari · Book 9: Times of the Prayers · As-Salat (the prayers) is expiation (of sins)
Narrated Ibn Mas`ud:
حَدَّثَنَا قُتَيْبَةُ ، قَالَ حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ ، عَنْ سُلَيْمَانَ التَّيْمِيِّ ، عَنْ أَبِي عُثْمَانَ النَّهْدِيِّ ، عَنِ ابْنِ مَسْعُودٍ ، أَنَّ رَجُلاً، أَصَابَ مِنَ امْرَأَةٍ قُبْلَةً، فَأَتَى النَّبِيَّ صلى الله عليه وسلم فَأَخْبَرَهُ، فَأَنْزَلَ اللَّهُ {أَقِمِ الصَّلاَةَ طَرَفَىِ النَّهَارِ وَزُلَفًا مِنَ اللَّيْلِ إِنَّ الْحَسَنَاتِ يُذْهِبْنَ السَّيِّئَاتِ} . فَقَالَ الرَّجُلُ يَا رَسُولَ اللَّهِ أَلِي هَذَا قَالَ " لِجَمِيعِ أُمَّتِي كُلِّهِمْ " .
A man kissed a woman (unlawfully) and then went to the Prophet (ﷺ) and informed him. Allah revealed: And offer prayers perfectly At the two ends of the day And in some hours of the night (i.e. the five compulsory prayers). Verily! good deeds remove (annul) the evil deeds (small sins) (11.114). The man asked Allah's Messenger (ﷺ), "Is it for me?" He said, "It is for all my followers."