The Record Book of the Righteous and Their Reward
Allah says that truly,
كَلَّ إِنَّ كِتَابَ الاَْبْرَارِ
Verily, the Record of Al-Abrar (the righteous believers)
These people are in a situation that is the opposite of the wicked people.
لَفِي عِلِّيِّينَ
is in `Illiyyin.
meaning, their final destination is `Illiyyin, which is the opposite of Sijjin.
It has been reported from Hilal bin Yasaf that Ibn Abbas asked Ka`b about Sijjin while he was present, and Ka`b said,
"It is the seventh earth and in it are the souls of the disbelievers."
Then Ibn `Abbas asked him about `Illiyyin, so he said,
"It is the seventh heaven and it contains the souls of the believers."
This statement -- that it is the seventh heaven -- has been said by others as well.
Ali bin Abi Talhah reported that Ibn `Abbas said concerning Allah's statement,
كَلَّ إِنَّ كِتَـبَ الاٌّبْرَارِ لَفِى عِلِّيِّينَ
(Nay! Verily, the Record of Al-Abrar (the righteous believers) is in `Illiyyin.)
"This means Paradise."
Others besides him have said,
"`Iliyyin is located at Sidrat Al-Muntaha."
The obvious meaning is that the word `Illiyyin is taken from the word `Uluw, which means highness. The more something ascends and rises, the more it becomes greater and increases.
Thus, Allah magnifies its affair and extols its matter by saying,
وَمَا أَدْرَاكَ مَا عِلِّيُّونَ