فَٱصْبِرْ إِنَّ وَعْدَ ٱللَّهِ حَقٌّ ۖ وَلَا يَسْتَخِفَّنَّكَ ٱلَّذِينَ لَا يُوقِنُونَ

The people of Makkah used to tell the Prophet, if he was really a prophet, he should perform a superhuman, supernatural miracle. But, this demand was not acceded to, because an exhibition of the paranormal was not expected to serve the real purpose. The real purpose of Islam was to ensure that people’s course of action changed, and such a change can be initiated only by bringing about a change in ways of thinking and not by stunning people with supernatural feats. The Quran, therefore, lays the utmost emphasis on reasoning. It wants to change the minds of the people on the strength of arguments. It wants to make people capable of seeing things in the proper perspective and of forming correct opinions. In fact, the real problem of man is that he falls short of right thinking. If right thinking is not engendered in man, even after seeing wonderful feats and miracles, he will utter the same foolish words in the same mindless manner as he did earlier. One’s heart being sealed means one’s not being capable of understanding things due to ignorance and wrong thinking. If an individual lacks the ability to form correct opinions, he can neither see things in their proper perspective nor learn fitting lessons from them. A subject of God who comes forward with the pure call for Truth always has to face a discouraging reaction from the people. The dayee talks exclusively of the Hereafter, while people’s minds are engaged in solving worldly problems. For this reason, people look down upon him. They always try to defeat him in every way, so much so that an atmosphere is created in which the preacher’s words appear to be lacking in weight. Such circumstances place the dayee in a situation of trial along with his addressees. At that time it becomes necessary for him not to lose his conviction. If, under the pressure of circumstances, he loses his conviction, he will start saying such things by way of compromise as may be important in the eyes of the general public, but which in the eyes of God will be of negligible importance.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (30:60)