To remind people of the establishment of the Hour and their resurrection from their graves to the gathering for the Day of Judgment, Allah says:

وَيَوْمَ يَحْشُرُهُمْ

(And on the Day when He shall gather (resurrect) them.) Similarly Allah said:

كَأَنَّهُمْ يَوْمَ يَرَوْنَ مَا يُوعَدُونَ لَمْ يَلْبَثُواْ إِلاَّ سَاعَةً مِّن نَّهَارٍ

(On the Day when they will see that (torment) with which they are promised (threatened, it will be) as if they had not stayed more than an hour in a single day.)46:35 Allah also said:

كَأَنَّهُمْ يَوْمَ يَرَوْنَهَا لَمْ يَلْبَثُواْ إِلاَّ عَشِيَّةً أَوْ ضُحَـهَا

(The Day they see it, (it will be) as if they had not tarried (in this world) except an afternoon or a morning.) 79:46

يَوْمَ يُنفَخُ فِى الصُّورِ وَنَحْشُرُ الْمُجْرِمِينَ يَوْمِئِذٍ زُرْقاً - يَتَخَـفَتُونَ بَيْنَهُمْ إِن لَّبِثْتُمْ إِلاَّ عَشْراً - نَّحْنُ أَعْلَمُ بِمَا يَقُولُونَ إِذْ يَقُولُ أَمْثَلُهُمْ طَرِيقَةً إِن لَّبِثْتُمْ إِلاَّ يَوْماً

(The Day when the Trumpet will be blown (the second blowing): that Day, We shall gather the criminals, blue eyed. They will speak in a very low voice to each other (saying): "You stayed not longer than ten (days)." We know very well what they will say, when the best among them in knowledge and wisdom will say: "You stayed no longer than a day!") 20:102-104 and,

وَيَوْمَ تَقُومُ السَّاعَةُ يُقْسِمُ الْمُجْرِمُونَ مَا لَبِثُواْ غَيْرَ سَاعَةٍ

(And on the Day that the Hour will be established, the criminals will swear that they stayed not but an hour.)30:55 These all are evidence of the brevity of the worldly life compared to the Hereafter. Allah said:

قَـلَ كَمْ لَبِثْتُمْ فِى الاٌّرْضِ عَدَدَ سِنِينَ - قَالُواْ لَبِثْنَا يَوْماً أَوْ بَعْضَ يَوْمٍ فَاسْأَلِ الْعَآدِّينَ - قَالَ إِن لَّبِثْتُمْ إِلاَّ قَلِيلاً لَّوْ أَنَّكُمْ كُنتُمْ تَعْلَمُونَ

(He (Allah) will say: "What number of years did you stay on earth" They will say: "We stayed a day or part of a day. Ask of those who keep account." He (Allah) will say: "You stayed not but a little, if you had only known!") 23:112-124 Allah then said:

يَتَعَارَفُونَ بَيْنَهُمْ

(They will recognize each other) The children will know their parents and relatives will recognize one another. They will know them just like they used to know them during the life in this world. However, on that Day everyone will be busy with himself. Allah then said:

فَإِذَا نُفِخَ فِى الصُّورِ فَلاَ أَنسَـبَ بَيْنَهُمْ

(Then, when the Trumpet is blown, there will be no kinship among them.)23:101 Allah also said:

وَلاَ يَسْـَلُ حَمِيمٌ حَمِيماً

(And no friend will ask a friend (about his condition).)70:10 Allah then said:

قَدْ خَسِرَ الَّذِينَ كَذَّبُواْ بِلِقَآءِ اللَّهِ وَمَا كَانُواْ مُهْتَدِينَ

(Ruined indeed will be those who denied the meeting with Allah and were not guided.) This is similar to the Ayah:

وَيْلٌ يَوْمَئِذٍ لِّلْمُكَذِّبِينَ

(Woe that Day to the deniers.)77:15 Woe to them because they will lose themselves and their families on the Day of Resurrection. That is indeed the great loss. There is no loss greater than the loss of one who will be taken away from his dear ones on the Day of Grief and Regret.