The fourth verse (12) has been revealed about a particular event. What happened was that the Mushriks of Makkah placed a host of demands before the Holy Prophet One of these was, ` our idols have been maligned in this Qur'an, therefore, we cannot believe in it. So, you should either bring some other Qur'an, or improve it by making alterations in it:;i ائْتِ بِقُرْآنٍ غَيْرِ هَـٰذَا أَوْ بَدِّلْ (Bring a Qur'an other than this, or change it - Yunus, 10:15) '. (Al-Baghawi, Mazhari)
Another demand they came up with was, ` we are to believe in your prophesy only when some treasure, like the treasures of the kings of the world, is sent down for you and which you dole out to everyone around. Or that some angel descends from the heavens and hangs out with you everywhere testifying that you were a Messenger of Allah in all certainty.'
The Holy Prophet ﷺ felt the pinch of these absurd, even disrespectfully audacious demands in his heart. The reason was that he was mercy for all the worlds. It was not possible for him to leave them to their fate and take out the hope that they might someday believe from his heart. Nor was it possible for him to fulfill their absurd demands. To begin with, these demands were based on bland irrationality. If idols, idol-worship and things like that are not called what they are, what would become of right guidance and how would it be done? And then this brain wave of demanding a treasure from a prophet was a loud miss-match with his mission. They had simply taken the station of a prophet on the analogy of the status of a king. Similarly, it is not the practice of Allah Ta'ala that He would create conditions under which people were materially compelled to start professing the Faith. Otherwise, the whole world is within His power and control. Who could dare profess a belief, and act according to it, against the will of Allah Ta` ala? But, it is in His infinite wisdom that He has made this world a place of test. No material means are used here to compel people to do something good or to abstain from something bad. Certainly, what is done here is through Scriptures and Apostles. Lines are drawn between virtue and vice. Good and bad are separated. The outcome of each is explained. That is how people are invited and exhorted to do what is right and abstain from what is evil. And if some angel were to be miraculously attached to a prophet to attest to the veracity of his word, it would have posed problems. When no one believed it, he would have faced cash punishment on the spot. In that case, this would have been a modality of compelling people to believe. This kind of belief would have not been believing without seeing which is the essence of belief and faith, nor would there be any choice left for man to make which is the essence of his deed. As for the demands of those people, they were, no doubt, absurd and audacious. But, there is another aspect to it. The very act of making such demands proved that these people were grossly unaware of the status and reality of a messenger and prophet of Allah. They saw no difference between Allah and His Messenger. They even took the messenger to be absolutely powerful like Allah, therefore, they demanded that he should do for them what could not be done by anyone other than Allah.
In brief, when the Holy Prophet ﷺ became very sad because of such demands, this verse was revealed to comfort him and to revitalize his thinking. Addressing him first, it was said: Would you - surrendering to the pressure of these people - leave out some part of the Qur'an, sent by Allah, which they do not like, such as a part where it talks about the utter helplessness of idols? Would you, then, still be disturbed in the face of such demands? The introduction of the statement in verse 12 with the word: aW (la'allaka: Is it then expected of you) does not mean that something like that could be expected of him actually. Instead, the purpose is to establish that he was free from such things. He would not leave out any part of the Qur'an in consideration of their insistence, nor does he have to be sad, concerned and straitened over their demands. The reason is that he has been sent from Allah as nadhir, as one who warns people against what is harmful for them, then, Allah takes care of the rest for He is powerful over everything. Nadhir has been mentioned here particularly because those being addressed were kafirs, and kafirs deserve nothing but warning against the consequences of their deeds. Otherwise, the Holy Prophet ﷺ is not simply nadhir, one who warns, he is bashir too, one who announces glad tidings for people who do good deeds. In addition to what has been said here about the mission of a nadhir, we should understand that, in reality, nadhir is a person who warns out of love and affection against what is evil and harmful. Therefore, in a way, the sense of bashir, a giver of glad tidings, is included in the sense of nadhir, a giver of warning.