أفمن زين له سوء عمله فرآه حسنا
Is he, then, to whom the evil of his deeds is made fair seeming, so that he considers it as good!
meaning, `such as disbelievers or immoral persons who do evil deeds and believe that they are doing something good, i.e., a person who is like that has been misguided by Allah, so what can you do for him? You cannot help him at all.'
فٳن الله يضل من يشاء ويهدي من يشاء
Verily, Allah sends astray whom He wills and guides whom He wills.
means according to His decree.
فﻼ تذهب نفسك عليهم حسرات
So destroy not yourself in sorrow for them.
means, do not grieve about that, for Allah is Wise in His decree and He leaves astray whomsoever He leaves astray, and He guides whomsoever He guides, and in doing so He has perfect knowledge and wisdom.
Allah says:
إن الله عليم بما يصنعون
Truly, Allah is the All-Knower of what they do!