رُوِيَ أَنَّ فَتَى مِنَ الأَنْصَارِ كَانَ يُصَلِّي الصَّلاَةَ مَعَ رَسُولِ اللّهِ (ص) وَ يَرْتَكِبُ الْفَوَاحِشَ فَوُصِفَ ذٌلِكَ لِرَسُولِ اللٌّهِ (ص) فَقَالَ إِنَّ صَلاَتَهُ تَنْهَاهُ يَوْماً مَا فَلَمْ يَلْبِثْ أَنْ تَابَ.
It has been reported that a youth from the Ansar, who used to offer his prayers with the Messenger of Allah (peace be upon him and his progeny), used to indulge in sinful and corrupt deeds. When this was brought to the notice of the Messenger of Allah (peace be upon him and his progeny), he said: “A day shall come when his prayers shall refrain him from committing sins. Before long, the youth repented.”
Biharul Anwar, Volume 82, Page 198