Let darkness and the shadow of death stain it; let a cloud dwell upon it; let the blackness of the day terrify it.
Let ... the shadow of death (deepest darkness, Isaiah 9:2)
Stain it. This is a later sense of the verb х gaa'al (H1350)] (Gesenius); better the old and more poetic idea, 'Let darkness (the ancient night of chaotic gloom) resume its rights over light (Genesis 1:2), a claim that day as its own.'
A cloud - collectively, a gathered mass of dark clouds. The blackness of the day terrify it - literally, the obscurations х kimriyreey (H3650)], whatever darkens the day (Gesenius). The verb in Hebrew [bi`eet] expresses sudden terrifying. May it be suddenly affrighted at its own darkness. Umbreit explains it of magical incantations that darken the day, forming the climax to the previous clauses; Job 3:8 speaks of cursers of the day similarly. But the former view is simpler. Others refer it to the poisonous Simoon wind.