Illa man thalama thumma baddala husnan baAAda soo-in fa-innee ghafoorun raheem (surah Naml: 11)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(27:11) unless, of course, someone has committed an offence." *14 Then, if after the evil, he changed (his act) into a good one, I am indeed AllForgiving, All-Merciful. *15

Illaa man zalama summa baddala husnam ba`da sooo`in fa innee Ghafoorur Raheem

*14) This exception can be contiguous as well as remote. In the first case it will imply that there can be a genuine cause of fear if the Messenger has committed an offence; in the second case it will mean: "None should have any cause of fear in My Presence, unless, of course, someone has committed an offence."
*15) That is, "If even an offender repents and reforms himself and does good instead of evil, I will pardon him. ' This implied both a warning and a good news. The Prophet Moses had killed a Copt inadvertently and fled from Egypt. This was an offence to which a subtle reference was made. When this offence was committed un-intentionally by the Prophet Moses, he had immediately offered repentance to Allah, saying, "O my Lord ! I have sinned against myself, so forgive me." So, "Allah forgave him" there and then. (Al-Qasas: 16). Here the good news of the same forgiveness has been given him, as if to say, "O Moses, there could be a genuine cause for you to feel afraid in My Presence, because you had committed an offence, but when you have changed the evil into good, I have nothing but forgiveness and mercy for you. I have not called you here at this time to punish you, but I am going to send you on a great mission with wonderful miracles."