Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(As for the disbelievers) who remain firm in their disbelief, (whether thou warn them), instil fear into them by means of the Qur'an, (or thou warm them not) or you do not instil fear into them, (it is all one for them; they believe not), they do not want to believe. It is also said that they will not believe as it is in Allah's knowledge.
Surely it is the same for those who disbelieve whether thou warnest them or thou warnest them not; they will not have faith.
From the beginning of the surah to this point is an allusion to the Lord's bounty and gentleness with familiars and friends. This verse alludes to His severity and justice toward the strangers and enemies.
God has both bounty and justice. If He acts with justice, that is fitting, and if He is bounteous, that is suitable for Him. But not everything that is fitting in justice is suitable for bounty, whereas everything suitable for bounty is fitting for justice. He calls one to bounty, and the decree is His. He drives another to justice, and the will is His. What is good is that bounty rules over justice, and justice is caught in bounty's hand. Justice is silent before bounty, and the ring of union is in bounty's ear. Do you not see that justice travels along with Him, and happy is he whose refuge is bounty? The fruit of bounty is felicity and triumph, and the result of justice is wretchedness and estrangement. Both are deeds already done. “The Pen has dried on what will be until the Day of Resurrection.” It is a beginningless decree and a work discarded and finished. “When someone's lot has set him down, his eagerness will not stir him up.”
The Pir of the Tariqah said, “O God, what will come of what You do not want? And when will he come whom you have not called? What does the unplanted get from water? What answer is given to the unworthy? What use to the bitter that sweet water is its neighbor? What gain to the thorn that the rose's fragrance is next to it? The apportioning has gone before, nothing to be added or taken away. What can be done? The Greatest Judge wants it this way. Satan lived in the highest horizon and performed thousands of acts of worship. What profit did it have, for he was not worthy. 'Since approval and wrath are beginningless attributes, there is no profit in shortened sleeves and determined steps.'”
One day ʿUmar KhaṬṬāb came across Iblis. He seized him by the collar and said, “I have been seeking you for a long time.
I want to take you home so that the children can play with you.”
Iblis said, “O ʿUmar, have respect for your elders! I worshiped God in the seven heavens, in each heaven for one hundred thousand years. I kept on going up, and I fancied that my going up was an honor and a caress. When I looked closely, the meaning was that the higher I went, the worse and the harder I would fall. O ʿUmar, you did not see my seven hundred thousand years of worship, but I saw you prostrating yourself before an idol.”
ʿUmar let him go, while the tongue of Iblis's state was saying in his abandonment,
“I said, 'My heart wants to be Your comrade,
so I will be worthy of thanks and applause.' By God, I did not think, O Spirit of the world,
As for the disbelievers, the likes of Abū Jahl, Abū Lahab and such; alike it is for them whether you have warned them or have not warned them, they do not believe, as God knows very well, so do not hope that they will believe (read a-andhartahum pronouncing both hamzas, or by not pronouncing the second, making it an alif instead, and inserting an alif between the one not pronounced and the other one, or leaving [this insertion]; al-indhār [‘warning’] is to give knowledge of something, and simultaneously instil an element of fear).
(Verily, those who disbelieve) meaning, covered the truth and hid it. Since Allah has written that they would do so, it does not matter if you (O Muhammad ) warn them or not, they would still have disbelieved in what you were sent with. Similarly, Allah said,
(And even if you were to bring to the People of the Book (Jews and Christians) all the Ayat, they would not follow your Qiblah (prayer direction)) (2:5).
These Ayat indicate that whomever Allah has written to be miserable, they shall never find anyone to guide them to happiness, and whomever Allah directs to misguidance, he shall never find anyone to guide him. So do not pity them - O Muhammad - deliver the Message to them. Certainly, whoever among them accepts the Message, then he shall gain the best rewards. As for those who turn away in rejection, do not feel sad for them or concerned about them, for
(Verily, those who disbelieve, it is the same to them whether you (O Muhammad ) warn them or do not warn them, they will not believe) "That the Messenger of Allah was eager for all the people to believe and follow the guidance he was sent with. Allah informed him that none would believe except for those whom He decreed happiness for in the first place, and none would stray except those who Allah has decreed to do so in the first place.''
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
That is, they refused to believe and fulfil all or any of the above mentioned six conditions.
It does not mean that Allah had sealed up their hearts, so they refused to believe. But it means that when they rejected the above-mentioned pre-requisites of belief and chose and adopted for themselves a way contrary to the one presented by the Qur'an, Allah sealed up their hearts and ears. The Qur'an simply states a law of Nature: if one takes a biased view of something and deliberately nourishes prejudices against it in his mind, he can neither see any virtue in it nor hear anything in its favour nor open his heart to consider it dispassionately. This is the law of Nature and, as it is Allah's law, the act of sealing up of the hearts and the ears and the covering of the eyes has been attributed to Him.
As for the disbelievers alike it is for them whether you have warned them or have not warned them they do not believe. Those who are veiled by the covering of their own qualities are kept from witnessing His truth. The allusion here is that both are the same to them - the words of one who tries to lead them to the Real ḥaqq or the words of one who aids them in seeking to attract worldly fortune ḥaẓẓ. Nay they are more inclined to the calls to heedlessness and prefer to pay attention to them. How could they not when they are marked with the branding of separation locked in the prison of absence and barred from the place of nearness. None of them will attain faith īmān because they have no security amān from the Real. Because they have not been granted security lam yuÌmanū they do not believe lam yuÌminū. A decision ḥukm God has already made is inalterable and a word from Him is final. [God's] power cannot be opposed. Fearsome attacks will surprise those who contest what has been decreed by the Real and the decision [of the Real] will catch them unaware. It is said that the disbeliever does not desist from his error because of the misery that is already his. Likewise the one who is bound by the shackles of his lower self is veiled from witnessing the unseen and His reality for he cannot see the right way or pursue the right course. It is said that for the one who remains in the darknesses of his foolishness the advice of sound guides and the fictions of those who speak falsely are equal to him for God has removed from his states the blessings of being able to judge between two things. He does not come with an ear to acceptance and pays little attention to the one who calls to right conduct. As it is said: My sincere advice naṣīḥatī is the concern of the sincere naṣūḥ. The disobedience of the sincere is My concern alone. It is also said that whoever has strayed from bearing witness to the favors that have been allotted to him imagines that the matter comes from what he does and does not do. [Such a person] relies on his own actions and is blind to witnessing [God's] gifts fa-ittakala ʿalā aʿmālihi wa-taʿāmā ʿan shuhūd afḌālihi.