Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(Those who disbelieve) the disbelievers of Mecca: Abu Jahl and his host (say: The Hour will never come unto us. Say) to them, O Muhammad: (Nay, by my Lord) Allah swore by Himself, (but it is coming) the Hour is coming (unto you surely. (He is) the Knower of the Unseen) He knows what is hidden from people. (Not an atom's weight) not even a small red ant, (or less than that or greater, escapes Him) is hidden from Allah (in the heavens or in the earth) as regard the works of the servants, (but it is in a clear Record) in the Guarded Tablet well preserved,
And those who disbelieve say, ‘The Hour, the Resurrection, will never come to us’. Say, to them: ‘Yes indeed, by my Lord, it shall come to you — [by] the Knower of the Unseen (read ‘ālimi’l-ghaybi as an adjectival qualification [of wa-rabbī, ‘by my Lord’], or read ‘ālimu’l-ghaybi, as the predicate of a [missing] subject [such as huwa, ‘He is’]; or read ‘allāmi’l-ghaybi). Not [even] the weight of an atom escapes, is hidden [from], Him in the heavens or in the earth, nor [is there] anything smaller than that or greater, but it is in a Manifest Book, namely, the Preserved Tablet (al-lawh al-mahfūz),
The Hour will come so that each Person will be rewarded or punished in accordance with His Deeds
This is one of three Ayat -- there is no fourth -- where Allah commands His Messenger to swear by His Almighty Lord that the resurrection will surely come, because the stubborn followers of disbelief denied that it would happen. One of these Ayat is in Surah Yunus, where Allah says:
(The disbelievers pretend that they will never be resurrected (for reckoning). Say: "Yes! By my Lord, you will certainly be resurrected, then you will be informed of what you did; and that is easy for Allah'') (64:7). And Allah says here:
قُلْ بَلَى وَرَبِّى لَتَأْتِيَنَّكُمْ
(Say: "Yes, by my Lord, it will come to you...'') Then Allah is described in a manner that affirms that:
(the All-Knower of the Unseen, not even the weight of a speck of dust or less than that or greater escapes His knowledge in the heavens or in the earth but it is in a Clear Book.) Mujahid and Qatadah said, "Nothing is hidden or concealed from Him.'' In other words, everything is encompassed by His knowledge, and nothing is hidden from Him. Even though bones may be scattered and disintegrate, He knows where they have gone and where they have dispersed, then He will bring them back just as He created them in the first place, because He has knowledge of all things. Then Allah tells us of His wisdom in re-creating bodies and bringing about the Hour, as He says:
(That He may recompense those who believe and do righteous good deeds. Those, theirs is forgiveness and generous provision. But those who strive against Our Ayat to frustrate them) meaning, those who try to turn others away from the path of Allah and who disbelieve His Messengers,
أُوْلَـئِكَ لَهُمْ عَذَابٌ مِّن رِّجْزٍ أَلِيمٌ
(those, for them will be a severe painful torment.) This means, He will bestow His favor upon the blessed, who are the believers, and will punish the doomed, who are the disbelievers. This is like the Ayah:
(And those who have been given knowledge see that what is revealed to you from your Lord is the truth,) This is another kind of wisdom, following on from the one before, which is that when those who believed in what was revealed to the Messengers see the onset of the Hour and how the righteous and the wicked will be rewarded and punished respectively, which they knew of beforehand in this world from the Books of Allah and which they are now seeing with their own eyes, they will say:
لَقَدْ جَآءَتْ رُسُلُ رَبِّنَا بِالْحَقِّ
(Indeed, the Messengers of our Lord did come with the truth) (7:43). And it will be said:
(And those who have been given knowledge see that what is revealed to you from your Lord is the truth, and that it guides to the path of the Exalted in might, Owner of all praise.) The Exalted in might is the One Who is All-Powerful, Whom none can overwhelm or resist, but He subjugates and controls all things. The Owner of All praise is the One Who, in all His words, deeds, laws and decrees, is deserving of praise, may He be glorified and exalted.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
This they said satirically and mockingly. What they meant was: "This Prophet has been giving us the news of his coming of Resurrection for along tune now, but Resurrection has not overtaken us so far although we have openly denied and rejected him as a Prophet, have been insolent to him and have ridiculed him in every way."
The use of the attribute "Knower of the unseen" for Allah while swearing by him by itself points to the fact that the coming of Resurrection is certain, but no one knows except Allah, Knower of the unseen, when exactly it will come. This same theme has been explained at different places in the Qur'an in various ways. For details, see AI-A'raf: 187, Ta Ha: 15. Luqman: 34, Al-Ahzab: 63, Al-hulk: 25-26, An-Naziyat: 42-44.
This is one of the arguments for the possibility of the Hereafter as is being stated in verse 7 below. One of the reasons why the deniers of the Hereafter regarded the life-after-death as irrational was ;' They said that when all human beings will have become dust after death, and scattered away in particles, how it will be possible to bring all the countless particles together and combine them to be re-created as the same human bodies once again. This doubt has been dispelled, saying, "Every particle wherever it is, is recorded in God's Register, and God knows where a particle is. Therefore, when He wills to recreate, He will not face any difficulty in gathering together all the particles of the body of each and every man. "
The above was an argument for the possibility of the Hereafter: this is an argument for its need and necessity. It means: A time must come when the wicked should be requited for their wickedness and the righteous rewarded for their righteousness. Reason wants and justice demands that a worker of goodness should be rewarded and a worker of evil punished. Now when you see that in the present worldly life neither is an evildoer fully requited for his evil nor a worker of goodness for his goodness, rather there are opposite results of evil and goodness in most cases, you should admit that this necessary demand of both reason and justice must be fulfilled at some time in the future. Resurrection and the Hereafter will be the same time. It is not its coming but its not coming which is contrary to reason and against justice.
In this connection, another point becomes evident from the preceding verses. They tell that the result of faith and righteous acts is forgiveness and a bounteous provision, and for those who strive and act antagonistically in order to discredit and defeat Allah's Religion, there will be a torment of the worst kind. This makes it manifest that he who believes sincerely will not be deprived of forgiveness even though he may not get a bounteous provision owing to some flaw or weakness in his deeds. And the one who is a disbeliever but who does not adopt an attitude of enmity and antagonism towards the true Faith, will not be able to avoid the torment but he will be saved from the worst torment.
That is, "These antagonists cannot succeed in their object to prove the truth presented by you false, however hard they may try, for they can only delude and misguide the ignorant people by their designs. Those possessed of knowledge cannot be deceived by them. "