We will overturn their hearts and sight, just as when they did not believe in it at first, and We will abandon them to wander blindly in their excessive insolence. ( Surat al-An‘am, 6:110)
We cannot know Allah and grasp the purpose of our existence if we lack knowledge about the religion with which He is pleased. Moreover, we cannot understand the divine purposes behind the creation of the universe and its countless inhabitants, life, death, the Hereafter, Paradise, Hell, angels, and Satan on our own. Many people live and die in heedlessness. However, if Allah places faith in our hearts, we find all of the answers to these questions. Allah then purifies our hearts and makes us sincere toward the religion. A person who used to be hostile to religion starts to be positive toward religion; one who used to ignore His commands begins to adhere to them meticulously and remembers Him continuously. Likewise, they start to thank Allah frequently for the blessings that they have received. Whereas before they disregarded the signs of Allah's existence, as well as His favors, mercy, and compassion, they now recognize all of these. In brief, sincere believers are like those people who wake up from sleep, for Allah moves them from unbelief to belief by placing faith in their hearts.
Just as Allah grants faith, He can remove it whenever He wills. Having faith depends upon remembering Allah, for only a heart that submits itself to Allah can find guidance. Unbelievers, lost in their delusions, cannot see or recognize the clear signs of Allah's existence all around them. In many verses, Allah states that such people's hearts are covered in such a way that they cannot grasp the truth:
Who could do greater wrong than someone who is reminded of the Signs of his Lord and then turns away from them, forgetting all that he has done before? We have placed covers on their hearts, preventing them from understanding it, and heaviness in their ears. Though you call them to guidance, they will nonetheless never be guided. ( Surat al-Kahf, 18:57)
Unbelievers sometimes admit that they cannot understand religion's message. The people of Prophet Shu‘ayb (as) is a clear example:
They said: “Shu‘ayb, We do not understand much of what you say, and we see that you are weak among us…” (Surah Hud, 11:91)
If one's heart is veiled and Allah hinders comprehension, then they can never be guided unless Allah wills otherwise. Allah calls attention to this, as follows:
Among them there are some who listen to you. But can you make the deaf hear, even though they cannot understand? Among them there are some who look at you. But can you guide the blind, even though they cannot see? (Surah Yunus, 10:42-43)
Allah causes the heart of those who desire faith and closeness to Him to yield to His remembrance and unites them with other Muslims. Meanwhile, He turns the hearts of those who are insincere toward unbelief. He has the power to turn the heart of anyone He wills at any time, and no one can change a heart that Allah has covered.
