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 ʿAbduka, wa ana ʿala ʿahdika wa waʿdika mastataʿtu, Aʿudhu bika min Sharri ma sanaʿtu, abu'u Laka biniʿmatika ʿalaiya, 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." (Using translation from Bukhārī 6306)   

أَنَّ رَسُولَ اللهِ ﷺ قَالَ سَيِّدُ الِاسْتِغْفَارِ أَنْ يَقُولَ الْعَبْدُ اللهُمَّ أَنْتَ رَبِّي لَا إِلَهَ إِلَّا أَنْتَ خَلَقْتَنِي وَأَنَا عَبْدُكَ وَعَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ أَبُوءُ لَكَ بِنِعْمَتِكَ وَأَبُوءُ لَكَ بِذَنْبِي فَاغْفِرْ لِي فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ فَإِنْ قَالَهَا بَعْدَمَا يُصْبِحُ مُوقِنًا فَمَاتَ مِنْ يَوْمِهِ قَبْلَ أَنْ يُمْسِيَ كَانَ فِي الْجَنَّةِ وَإنْ قَالَهَا حِينَ يُمْسِي فَمَاتَ قَبْلَ أَنْ يُصْبِحَ كَانَ فِي الْجَنَّةِ خَالَفَهُ الْوَلِيدُ بْنُ ثَعْلَبَةَ رَوَاهُ عَنْ عَبْدِ اللهِ بْنِ بُرَيْدَةَ عَنْ أَبِيهِ  

The Prophet ﷺ said: If anyone says in the morning or in the evening: "O Allah! Thou art my Lord; there is no god but Thee, Thou hast created me, and I am Thy servant and hold to Thy covenant and promise as much as I can; I seek refuge in Thee from the evil of what I have done: I acknowledge Thy favour to me, and I acknowledge my sin; pardon me, for none but Thee pardons sins, and dies during the daytime or during the night." he will go to Paradise. (Using translation from Abū Dāʾūd 5070)  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ قَالَ اللهُمَّ أَنْتَ رَبِّي لَا إِلَهَ إِلَّا أَنْتَ خَلَقْتَنِي وَأَنَا عَبْدُكَ وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ أَبُوءُ بِنِعْمَتِكَ وَأَبُوءُ بِذَنْبِي فَاغْفِرْ لِي فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ فَمَاتَ مِنْ يَوْمِهِ وَلَيْلَتِهِ دَخَلَ الْجَنَّةَ