Narrated Shaddad bin Aus:
The Prophet (ﷺ) said "The most superior way of asking for forgiveness from Allah is: 'Allahumma anta Rabbi la ilaha illa anta, Khalaqtani wa ana Abduka, wa anaala ahdika wa wadika mastatatu, Audhu bika min Sharri ma sanatu, abu'u Laka binimatika `alaiya, wa abu'u laka bidhanbi faghfir lee fa innahu la yaghfiru adhdhunuba illa anta." The Prophet (ﷺ) added. "If somebody recites it during the day with firm faith in it, and dies on the same day before the evening, he will be from the people of Paradise; and if somebody recites it at night with firm faith in it, and dies before the morning, he will be from the people of Paradise."
(Sahih al-Bukhari 6306)
اللَّهُمَّ أَنْتَ رَبِّي، لاَ إِلَهَ إِلاَّ أَنْتَ، خَلَقْتَنِي وَأَنَا عَبْدُكَ، وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ، أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ، أَبُوءُ لَكَ بِنِعْمَتِكَ عَلَىَّ وَأَبُوءُ لَكَ بِذَنْبِي، فَاغْفِرْ لِي، فَإِنَّهُ لاَ يَغْفِرُ الذُّنُوبَ إِلاَّ أَنْتَ
