((مَا مِنْ عَبْدٍ يُذنِبُ ذَنْباً فَيُحْسِنُ الطُّهُورَ، ثُمَّ يَقُومُ فَيُصَلِّي رَكْعَتَيْنِ، ثُمَّ يَسْتَغْفِرُ اللَّهَ إِلاَّ غَفَرَ اللَّهُ لَهُ)).
Translation
(Any servant who commits a sin and as a result, performs ablution, prays two units of prayer (i.e. two rakAAas) and then seeks Allah’s forgiveness, Allah would forgive him.)
Source
Hisnul Muslim (Fortress of the Muslim), No. 140 — chapter “What to say and do if you commit a sin”. hisnmuslim.com
Related Duas
Repentance and seeking forgiveness
Supplication 1 of 6
قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم: ((وَاللَّهِ إِنِّي لأَسْتَغفِرُ اللَّهَ وَأَتُوبُ إِلَيْهِ فِي الْيَوْمِ أَكْثَرَ مِنْ سَبْعِينَ مَرَّةٍ)).
(The Messenger of Allah said: ‘By Allah, I seek forgiveness and repent to Allah, more than seventy times a day.)
Hisnul Muslim · No. 248
((وَلَكَ)).
(AAabdullah Ibn Sarjis said: ‘I went to see the Prophet and ate from his food and then said to him: (May Allah forgive you, O Messenger of Allah.) he replied: (and you.))
Hisnul Muslim · No. 197