Repentance and forgiveness (tawbah)

وَإِذْ قَالَ مُوسَىٰ لِقَوْمِهِۦ يَـٰقَوْمِ إِنَّكُمْ ظَلَمْتُمْ أَنفُسَكُم بِٱتِّخَاذِكُمُ ٱلْعِجْلَ فَتُوبُوٓا۟ إِلَىٰ بَارِئِكُمْ فَٱقْتُلُوٓا۟ أَنفُسَكُمْ ذَٰلِكُمْ خَيْرٌ لَّكُمْ عِندَ بَارِئِكُمْ فَتَابَ عَلَيْكُمْ ۚ إِنَّهُۥ هُوَ ٱلتَّوَّابُ ٱلرَّحِيمُ

And [recall] when Moses said to his people, "O my people, indeed you have wronged yourselves by your taking of the calf [for worship]. So repent to your Creator and kill yourselves [i.e., the guilty among you]. That is best for [all of] you in the sight of your Creator." Then He accepted your repentance; indeed, He is the Accepting of Repentance, the Merciful.

وَٱلَّذَانِ يَأْتِيَـٰنِهَا مِنكُمْ فَـَٔاذُوهُمَا ۖ فَإِن تَابَا وَأَصْلَحَا فَأَعْرِضُوا۟ عَنْهُمَآ ۗ إِنَّ ٱللَّهَ كَانَ تَوَّابًا رَّحِيمًا

And the two who commit it [i.e., unlawful sexual intercourse] among you - punish [i.e., dishonor] them both. But if they repent and correct themselves, leave them alone. Indeed, Allāh is ever Accepting of Repentance and Merciful.

وَءَاخَرُونَ مُرْجَوْنَ لِأَمْرِ ٱللَّهِ إِمَّا يُعَذِّبُهُمْ وَإِمَّا يَتُوبُ عَلَيْهِمْ ۗ وَٱللَّهُ عَلِيمٌ حَكِيمٌ

And [there are] others deferred until the command of Allāh - whether He will punish them or whether He will forgive them. And Allāh is Knowing and Wise.

إِلَّا ٱلَّذِينَ تَابُوا۟ مِنۢ بَعْدِ ذَٰلِكَ وَأَصْلَحُوا۟ فَإِنَّ ٱللَّهَ غَفُورٌ رَّحِيمٌ

Except for those who repent thereafter and reform, for indeed, Allāh is Forgiving and Merciful.