(4) باب الصَّلاَةُ كَفَّارَةٌ
Narrated Ibn Mas`ud:
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."
Reference: Sahih al-Bukhari 526
In-book reference: Book 9, Hadith 5
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 10, Hadith 504