“Do not despair of the mercy of Allah. Indeed, Allah forgives all sins.”

Say, "O My servants who have transgressed against themselves by sinning, do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."

The address is the striking part. The people spoken to have wronged themselves badly — the verse says they went beyond every limit — and Allah still calls them “My servants.” The commentators tie the promise to the command that comes immediately after it: turn back to your Lord and submit to Him. So the forgiveness of all sins is the forgiveness of all sins repented from. The verse itself names no exception and sets no ceiling.