But those who reject Faith after they accepted it, and then go on adding to their defiance of Faith,- never will their repentance be accepted; for they are those who have (of set purpose) gone astray.
The removal of a doubt:
On a superficial view of the verse :’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. (Bayan al-Quran)
Shafi, Muhammad (2008). Maariful Quran. (Vol .2 surah 3 pg. 108-109). English-MaarifulQuran-MuftiShafiUsmaniRA-Vol-2.pdf (islamicweblibrary.com)