What to Say and Do After Committing a Sin

((مَا مِنْ عَبْدٍ يُذنِبُ ذَنْباً فَيُحْسِنُ الطُّهُورَ، ثُمَّ يَقُومُ فَيُصَلِّي رَكْعَتَيْنِ، ثُمَّ يَسْتَغْفِرُ اللَّهَ إِلاَّ غَفَرَ اللَّهُ لَهُ)).

There is no slave who commits a sin, then performs ablution well, then stands and prays two rak'ahs, then seeks Allah's forgiveness, but Allah will forgive him.