Surat Al-An'aam (The Cattle) - الأنعام

وَإِذَا جَآءَكَ ٱلَّذِينَ يُؤْمِنُونَ بِـَٔايَٰتِنَا فَقُلْ سَلَٰمٌ عَلَيْكُمْ كَتَبَ رَبُّكُمْ عَلَىٰ نَفْسِهِ ٱلرَّحْمَةَ أَنَّهُۥ مَنْ عَمِلَ مِنكُمْ سُوٓءًۢا بِجَهَٰلَةٍ ثُمَّ تَابَ مِنۢ بَعْدِهِۦ وَأَصْلَحَ فَأَنَّهُۥ غَفُورٌ رَّحِيمٌ ﴿٥٤﴾

And when those who believe in Our communications come to you, say: Peace be on you, your Lord has ordained mercy on Himself, (so) that if any one of you does evil in ignorance, then turns after that and acts aright, then He is Forgiving, Merciful.