Translation of the verse 18 from Surah Al-Muzzammil : Number of verses 20 - - page 574 - Part 29.
Whereon the heaven will be cleft asunder? His Promise is certainly to be accomplished.
The heaven will break apart therefrom; ever is His promise fulfilled.
(73:18) the Day whose severity shall cause the heaven to split asunder? Allah's promise is ever bound to be fulfilled.
Source : Al-Muzzammil Verse 18: The heaven will break apart therefrom; ever is His promise fulfilled.