يوم يجمعكم ليوم الجمع
The Day when He will gather you on the Day of Gathering,
meaning the Day of Resurrection. This is the Day when the earlier and later generations will all be gathered in one area, a caller would be heard by them all, and one's vision would easily see them all.
Allah said,
ذلك يوم مجموع له الناس وذلك يوم مشهود
That is the Day whereon mankind will be gathered together, that is a Day when all will be present. (11:103)
and,
قل إن اﻻولين واﻻخرين
لمجموعون إلى ميقت يوم معلوم
Say:
"(Yes) verily, those of old, and those of later times. All will surely be gathered together for appointed meeting of a known Day.'' (56:49-50)
Allah's statement,
ذلك يوم التغابن
that will be the Day of At-Taghabun.
Ibn `Abbas said,
"It is one of the names of the Day of Judgement, and that is because the people of Paradise will have gained over the people of the Fire.''
Qatadah and Mujahid said similarly.
Muqatil bin Hayyan said,
"There is no mutual loss and gain greater than these entering Paradise and those being taken to the Fire.''
Allah explained His statement saying;
ومن يومن بالله ويعمل صالحا يكفر عنه سيياته
ويدخله جنات تجري من تحتها اﻻنهار خالدين فيها أبدا
ذلك الفوز العظيم
والذين كفروا وكذبوا باياتنا أوليك أصحاب النار خالدين فيها وبيس المصير