Why are non-Muslims asked to believe in Islam, even though Muslims are not asked not to read about other religions? And will the righteous person who was not reached by Islam be judged in the same way as one who was reached by it and disbelieved?

The certainty and tranquility of a Muslim are not equal to those of a non-Muslim, because Muslims alone possess a preserved revelation from Allah Almighty and a clear Book that brings them out of darkness into light, and opens their hearts to Islam. Non-Muslims, on the other hand, do not have a proof based on the truthfulness of their religions.

Heraclius acknowledged this fact by the Muslims not abandoning their religion, because once faith mixes with hearts, it becomes firm within them. This is in contrast to disbelievers whose religion does not align with sound human nature (fitra) and intellect. Therefore, there can be no equality between truth and falsehood. The Muslim’s religion conforms to fitra and intellect, thus it is stable, while the disbeliever has a deficiency that can only be remedied by true faith.

As for non-Muslims who heard about Islam but did not embrace it, they fall into different categories, and their rulings regarding the establishment of proof and salvation in the Hereafter vary.