﴿ وَٱلَّيْلِ إِذَا يَغْشَىٰهَا ﴾

“and the night as it veils it darkly!”

The fourth oath is taken thus: وَاللَّيْلِ إِذَا يَغْشَاهَا (and by the night when it envelops him,...91:4). In other words, when it [ the night ] sets in, the brightness of the sun is concealed [ and only darkness prevails ]. '