يَوْمَ نَطْوِي السَّمَاءَ كَطَيِّ السِّجِلِّ لِلْكُتُبِ (The Day when We roll up the sky like a scroll rolls up the writings. - 21:104.) According to Sayyidna Ibn ` Abbas ؓ the word سِّجِلِّ means a sheet of a book. ` Ali Ibn Abi Talhah, 'Aufi’, Mujahid, Qatadah, Ibn Jarir and Ibn Kathir have all adopted the same meaning of the word. The word کُتُب in the verse is used for المَکتُوب that is something written. So the meaning of the verse is that the sky will be rolled up like a scroll with its writings. (Ibn Kathir)
Sahih al-Bukhari contains a story on the authority of Sayyidna ` Abdullah Ibn ` Umar ؓ that the Holy Prophet ﷺ said that on the Day of Judgment Allah Ta` ala would roll up all the seven skies and the seven worlds along with all the created things thereon in His hand, and all of them together would be no more than a grain of rye in His hand. (Ibn Kathir)