It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The strongest supplication is that you say: «اللَّهُمَّأَنْتَرَبِّي،أَنَاعَبْدُكَ،ظَلَمْتُنَفْسِي،وَاعْتَرَفْتُبِذَنْبِي،فَإِنَّهُلَايَغْفِرُالذُّنُوبَإِلَّاأَنْتَ،رَبِّاغْفِرْلِي» 'O Allah! You are my Lord and I am Your servant. I have wronged myself and I admit my sin. None forgives sins except You. O my Lord! Forgive me.'"