Commentary
The removal of a doubt:
On a superficial view of the verse كَيْفَ يَهْدِي اللَّـهُ : 'How shall Allah give guidance...' (86), there emerges a doubt that whoever turns an apostate receives no guidance afterwards, although, the fact is contrary to this. There are many who, after having become apostates, re-embrace the faith and become recipients of guidance.
The answer is that the withholding of guidance mentioned here is in accordance with common usage. For instance, some criminal when punished by a certain ruler may say, 'I have been given a special treatment by the ruler with his own hands.' And in answer to him, it is said: 'Why are we going to give a special treatment to such a criminal?' That is, there is just no special treatment called for in this case, while it does not mean that such a person cannot, in any way, become deserving of special treatment even if he behaved well. (Bayern a1-Qur'an)