Thou shalt not be afraid for the terror by night; nor for the arrow that flieth by day; The terror by night - Night is a time of terrors, because it is a time of treasons, plunder, robbery, and murder. The godly man lies down in peace, and sleeps quietly, for he trusts his body, soul, and substance, in the hand of God; and he knows that he who keepeth Israel neither slumbers nor sleeps. It may also mean all spiritual foes, - the rulers of the darkness of this world. I have heard the following petition in an evening family prayer: "Blessed Lord, take us into thy protection this night; and preserve us from disease, from sudden death, from the violence of fire, from the edge of the sword, from the designs of wicked men, and from the influence of malicious spirits!"
Nor for the arrow - The Chaldee translates this verse, "Thou shalt not fear the demons that walk by night; nor the arrow of the angel of death which is shot in the day time." Thou needest not to fear a sudden and unprovided-for death.