Allah tells us of the terrors of the Day of Resurrection, and the awesome things that will come to pass, as He says elsewhere:
يَوْمَ تَمُورُ السَّمَآءُ مَوْراً - وَتَسِيرُ الْجِبَالُ سَيْراً
(On the Day when the heaven will shake with a dreadful shaking, And the mountains pass moving away.) 52:9-10 meaning, they will move from their places and will vanish. As Allah says:
وَتَرَى الْجِبَالَ تَحْسَبُهَا جَامِدَةً وَهِىَ تَمُرُّ مَرَّ السَّحَابِ
(And you will see the mountains and think them solid, but they shall pass away as the passing away of the clouds.) 27:88
وَتَكُونُ الْجِبَالُ كَالْعِهْنِ الْمَنفُوشِ
(And the mountains will be like carded wool.) 101:5
وَيَسْـَلُونَكَ عَنِ الْجِبَالِ فَقُلْ يَنسِفُهَا رَبِّى نَسْفاً - فَيَذَرُهَا قَاعاً صَفْصَفاً - لاَّ تَرَى فِيهَا عِوَجاً وَلا أَمْتاً
(And they ask you about the mountains, say: "My Lord will pulverize them scattering their dust. To leave them as a barren plain. You will not see in it crookness or curve.) 20:105-107 Allah tells us that He will cause the mountains to vanish and be levelled, and the earth will be left as a smooth plain, a level surface with nothing crooked or curved therein, no valleys or mountains. So Allah says:
وَتَرَى الاٌّرْضَ بَارِزَةً
(and you will see the earth as a levelled plain, ) meaning clear and open, with no features that anyone may recognize and nothing for anyone to hide behind. All creatures will be visible to their Lord, and not one of them will be hidden from Him. Mujahid and Qatadah said,
وَتَرَى الاٌّرْضَ بَارِزَةً
(and you will see the earth as a levelled plain,) "No one will be hidden or absent." Qatadah said, "There will be no buildings and no trees."
وَحَشَرْنَـهُمْ فَلَمْ نُغَادِرْ مِنْهُمْ أَحَداً
(and we shall gather them, so that We will not leave one of them behind.) means, `We shall gather them all, the first of them and the last of them, and We shall not leave anyone behind, young or old.' As Allah says:
قُلْ إِنَّ الاٌّوَّلِينَ وَالاٌّخِرِينَ - لَمَجْمُوعُونَ إِلَى مِيقَـتِ يَوْمٍ مَّعْلُومٍ
(Say: "(yes) verily, those of old, and those of later times. All will surely be gathered together for an appointed meeting of a known Day.) 56:49,50
ذلِكَ يَوْمٌ مَّجْمُوعٌ لَّهُ النَّاسُ وَذَلِكَ يَوْمٌ مَّشْهُودٌ
(That is a Day whereon mankind will be gathered together, and that is a Day when all will be present) 11:103.
وَعُرِضُواْ عَلَى رَبِّكَ صَفَا
(And they will be set before your Lord, aligned.) This may mean that all of creation will stand before Allah in one row, as Allah says:
يَوْمَ يَقُومُ الرُّوحُ وَالْمَلَـئِكَةُ صَفّاً لاَّ يَتَكَلَّمُونَ إِلاَّ مَنْ أَذِنَ لَهُ الرَّحْمَـنُ وَقَالَ صَوَاباً
(The Day that Ar-Ruh (Jibril) and the angels will stand aligned, they will not speak except him whom the Most Gracious (Allah) allows, and he will speak what is right) 78:38; or it may mean that they will stand in rows, as Allah says:
وَجَآءَ رَبُّكَ وَالْمَلَكُ صَفّاً صَفّاً
(And your Lord comes with the angels in rows.) 89:22
لَّقَدْ جِئْتُمُونَا كَمَا خَلَقْنَـكُمْ أَوَّلَ مَرَّةٍ
(Now indeed, you have come to Us as We created you the first time.) This is a rebuke to those who denied the Hereafter, a reprimand before all creation. This is why Allah says to them:
بَلْ زَعَمْتُمْ أَلَّن نَّجْعَلَ لَكُمْ مَّوْعِدًا
(Nay, but you thought that We had appointed no meeting for you (with Us).), meaning, you did not think that this would happen to you or that it would come to pass.
وَوُضِعَ الْكِتَـبُ
(And the Book will be produced,) the Book of deeds, which contains a record of everything, major or minor, significant or insignificant, great or small.
فَتَرَى الْمُجْرِمِينَ مُشْفِقِينَ مِمَّا فِيهِ
(and you will see the criminals, fearful of that which is therein.) of their evil deeds and reprehensible actions.
وَيَقُولُونَ يوَيْلَتَنَا
(They will say, "Woe to us!") expressing words of regret for having wasted their lives.
مَا لِهَـذَا الْكِتَـبِ لاَ يُغَادِرُ صَغِيرَةً وَلاَ كَبِيرَةً إِلاَّ أَحْصَاهَا
(What sort of Book is this that leaves neither a small thing nor a large thing, but has recorded it with numbers!) it has left no sin, major or minor, and no action, no matter how small, but it has recorded it with the utmost precision and accuracy.
وَوَجَدُواْ مَا عَمِلُواْ حَاضِرًا
(And they will find all that they did, present,) everything, both good and evil, as Allah says,
يَوْمَ تَجِدُ كُلُّ نَفْسٍ مَّا عَمِلَتْ مِنْ خَيْرٍ مُّحْضَرًا
(On the Day when every person will be confronted with all the good he has done) 3:30. Allah says:
يُنَبَّأُ الإِنسَـنُ يَوْمَئِذِ بِمَا قَدَّمَ وَأَخَّرَ
(On that Day man will be informed of what he sent forward, and what he left behind.) 75:13 And Allah says:
يَوْمَ تُبْلَى السَّرَآئِرُ
(The Day when all the secrets will be exposed. ) 86:9 meaning, everything that is hidden in people's hearts will become known. Imam Ahmad recorded from Anas that the Prophet said,
«لِكُلِّ غَادِرٍ لِوَاءٌ يَوْمَ الْقِيَامَةِ يُعْرَفُ بِه»
(Every traitor will have a banner on the Day of Resurrection, by which he will be known.) It was also narrated in the Two Sahihs, where one narration says,
«يُرْفَعُ لِكُلِّ غَادِرٍ لِوَاءٌ يَوْمَ الْقِيَامَةِ عِنْدَ اسْتِهِ بِقَدْرِ غَدْرَتِهِ، يُقَالُ: هَذِهِ غَدْرَةُ فُلَانِ بْنِ فُلَان»
(On the Day of Resurrection, for every traitor a banner will be erected by his backside, and it will be said, "This is the betrayer of so-and-so the son of so-and-so.")
وَلاَ يَظْلِمُ رَبُّكَ أَحَدًا
(and your Lord treats no one with injustice.) means, He will judge between His creatures for all of their deeds, and He will not treat any of His creatures with injustice. He will overlook and forgive and have mercy, and He will punish whomever He wills by His power, wisdom and justice. He will fill Hell with the disbelievers and those who have been disobedient. Then He will rescue the disobedient, and leave the disbelievers there for eternity. He is the Judge Who never wrongs or oppresses. Allah says:
إِنَّ اللَّهَ لاَ يَظْلِمُ مِثْقَالَ ذَرَّةٍ وَإِن تَكُ حَسَنَةً يُضَـعِفْهَا
(Surely, Allah wrongs not even of the weight of a speck of dust, but if there is any good, He doubles it.) 4:40
وَنَضَعُ الْمَوَزِينَ الْقِسْطَ لِيَوْمِ الْقِيَـمَةِ فَلاَ تُظْلَمُ نَفْسٌ شَيْئاً
(And We shall set up Balances of justice on the Day of Resurrection, then none will be dealt with unjustly in anything.) Until His saying;
حَـسِبِينَ
(to take account) 21:47 And there are many similar Ayat. Imam Ahmad recorded that `Abdullah bin Muhammad bin `Aqil heard Jabir bin `Abdullah say, "I was told about a Hadith which a man heard from the Prophet , so I bought a camel and put my saddle on it, then I traveled on it for a month until I came to Ash-Sham, where `Abdullah bin Unays was. I said to the doorkeeper, `Tell him that Jabir is at the door.' He said, `Jabir bin `Abdullah' I said, `Yes.' So he came out, still putting his garment on, and embraced me, and I embraced him, and said: `I heard a Hadith narrated by you, that you heard from the Messenger of Allah ﷺ about reciprocal punishments. I was afraid that you or I would die before I could hear it.' He said, `I heard the Messenger of Allah ﷺ say:
«يَحْشُرُ اللهُ عَزَّ وَجَلَّ النَّاسَ يَوْمَ الْقِيَامَةِ أَوْ قَالَ: الْعِبَادَ عُرَاةً غُرْلًا بُهْمًا»
(Allah will gather the people -- or His servants -- on the Day of Resurrection, naked, uncircumcised and Buhman.) I asked, `What is Buhman' He said,
لَيْسَ مَعَهُمْ شَيْءٌ، ثُمَّ يُنَادِيهِمْ بِصَوْتٍ يَسْمَعُهُ مَنْ بَعُدَ كَمَا يَسْمَعُهُ مَنْ قَرُبَ: أَنَا الْمَلِكُ، أَنَا الدَّيَّانُ لَا يَنْبَغِي لِأَحَدٍ مِنْ أَهْلِ النَّارِ أَنْ يَدْخُلَ النَّارَ وَلَهُ عِنْدَ أَحَدٍ مِنْ أَهْلِ الْجَنَّةِ حَقٌّ حَتَّى أُقِصَّهُ مِنْهُ، وَلَا يَنْبَغِي لِأَحَدٍ مِنْ أَهْلِ الْجَنَّةِ أَنْ يَدْخُلَ الْجَنَّةَ وَلَهُ عِنْدَ رَجُلٍ مِنْ أَهْلِ النَّارِ حَقٌّ حَتَّى أُقِصَّهُ مِنْهُ حَتَّى اللَّطْمَة»
(They will have nothing with them. Then a voice will call out to them that will be heard by those far away just as easily as it will be heard by those near: "I am the Sovereign, I am the Judge. None of the people of Hell should enter Hell if he is owed something by one of the people of Paradise, until I have settled the matter, and none of the people of Paradise should enter Paradise if he is owed something by one of the people of Hell, until I settle the matter -- even if it is only the case of a slap.") We said, `How will that be, when we have come before Allah barefooted, naked, uncircumcised and having nothing with us' He said,
«بِالْحَسَنَاتِ وَالسَّيِّئَات»
(By merit for good deeds, and recompense for evil deeds.) Shu`bah narrated from Al-`Awwam bin Muzahim from Abu `Uthman from `Uthman bin `Affan, may Allah be pleased with him, that the Messenger of Allah ﷺ said:
«إِنَّ الْجَمَّاءَ لَتَقْتَصُّ مِنَ الْقَرْنَاءِ يَوْمَ الْقِيَامَة»
(The animal who lost a horn will settle the score with the one that has horns on the Day of Resurrection.) It was recorded by `Abdullah the son of Imam Ahmad, and there are corroborating narrations through other routes.