Are the people of a region who hold beliefs of kufr (disbelief) and think they are Muslims, and have not heard of true Islam, excused? Will they abide eternally in Hellfire, or will they be tested in the Hereafter like those whom the message of Islam did not reach? Or are they not excused merely because they have heard of the religion of Islam?

The issue of excuse by ignorance regarding the fundamentals of religion requires verification. The ruling on it varies depending on whether the proof has reached the accountable individual, the clarity of the matter, and people's cognitive abilities. Once a person's Islam is established, it is not removed except by the establishment of proof, the removal of doubt, and the absence of impediments to declaring disbelief. This applies to both the fundamentals and the ancillary matters. Thus, whoever denies the obligation of the four main pillars of Islam or the prohibition of matters established by continuous transmission after the proof has reached him, disbelieves. As for one who has not received the proof, such as a new convert to Islam or someone raised in a remote desert, or one who falls into a mistaken interpretation, he is asked to repent and the proof is established against him. If he persists, he disbelieves, but he is not judged to be a disbeliever before that.