In the third verse (30), it was said that there are people Allah has guided right while there are others who have provided the proof of their erroneous conduct, because they have, bypassing Allah, made satans their comrades, and they presume that they are on the right path.

The sense is that the guidance of Allah Subhanahu wa Ta` ala was open to all, but they turned away from it and started following satans, then, on top of it, they were led to think that their sickness was health, and their error, guidance.

This verse tells us that not knowing the injunctions of the Shari` ah is no valid excuse. If someone takes to a way of error thinking it to be correct with full sincerity, he will not be considered excusable in the sight of Allah. - because Allah has given everyone reason and common-sense to use it and distinguish the true from the false. Then, man was not left to rely on his reason alone. He sent prophets and books. They made the right and wrong and the true and false all too clear.

Now someone may doubt that a person who is acting in good faith, though in error, should not have any blame coming to him. He should be excused because he is not aware of his error. The answer is that Allah Ta` ala has blessed human beings with reason and sense with the added benefit of the teachings of the noble prophets, may peace be upon them all. At least, through these, he should be able to compare his method and way with that suggested by them. There has to be some doubt or pinch or question in his mind. Now, his fault is that he did not pay any attention to what they taught and kept sticking to the way of error he had taken to.

However, a person who has striven his best in the quest of truth, yet failed to find the right path and true teaching, may be found excusable in the sight of Allah - as Imam al-Ghazali has said in his book, Al-Tafriqah Bayn al-Islam wa Al-zandaqah واللہ اَعلَم .