Commentaries:
Barnes' Notes
Thou shalt not be afraid for the terror by night - That which usually causes alarm at night - a sudden attack; an unexpected incursion of enemies; sudden disease coming on by night; or the pestilence which seems to love night, and to "walk in darkness." Any one of these things seems to be aggravated by night and darkness; and hence, we most dread them then. We cannot see their approach; we cannot measure their outlines; we know not the extent of the danger, or what may be the calamity.
Nor for the arrow that flieth by day - Whether shot from the bow of God - as pestilence and disease; or from the hand of man in battle. The idea is, that he that trusts in God will be calm. Compare the notes at Psalms 56:3.
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.