King James Bible
"Thou shalt not be afraid for the terror by night; nor for the arrow that flieth by day;"
The psalmist promises freedom from fear of nocturnal dangers—whether supernatural threats, enemy raids, or plague that ancient peoples associated with darkness. Night terrors represent the unseen, unpredictable threats that typically cause the most anxiety. Daylight brings its own dangers, here symbolized by arrows—visible, swift attacks from human enemies. This completes a merism (night/day) indicating God's protection extends through all hours, against both hidden and open threats.