Tafsir of An-Naba' 78:10

"And We made the night"—in which sleep usually occurs—"a garment," covering you with its darkness just as a garment covers you. It is possible that the garment to which it is likened is what one covers oneself with during sleep, such as a quilt or the like, for the resemblance of the night to this is more complete and more pertinent to the realization of the intended purpose. Many have chosen the broader meaning, that We made it a cover for you from [the sight of] eyes when you desire to escape from an enemy, or to launch a night attack against one, or to conceal things you do not wish to be seen regarding many affairs.

Al-Mutanabbi counted among the blessings of the night the ability to conduct night raids on enemies and to attain the favor of a beloved and meet them, refuting the well-known doctrine of the Manichaeans—that good is attributed to light and evil to darkness in the known sense—by saying: How many a favor has the darkness of the night bestowed upon me, Proving that the Manichaeans are liars! It protected you from the malice of enemies while you marched against them, And therein, the coy beloved visited you.

Some have suggested that the night being like a garment could mean it is like a garment for the day in the ease of its removal; yet its far-fetched nature is not hidden. Among the things that evoke wonder is the deduction some have made from this verse that whoever prays naked in the night or in darkness has a valid prayer. By my life, he has strayed far from the garment of truth, as is not hidden from one upon whom the light of true reality has shone.