(Qasas) 28 : 16
قَالَ رَبِّ إِنِّي ظَلَمْتُ نَفْسِي فَاغْفِرْ لِي فَغَفَرَ لَهُ ۚ إِنَّهُ هُوَ الْغَفُورُ الرَّحِيمُ
He prayed: "My Lord, indeed I have wronged myself, so You forgive me", and He forgave him; indeed, He is the Forgiving, the Merciful.
See explanation 2: 256; 3: 101-102, 190-191; 7: 23 and 21: 87.