Albert Barnes Commentary Psalms 91:7

"A thousand shall fall at thy side, And ten thousand at thy right hand; [But] it shall not come nigh thee." — Psalms 91:7 (ASV)

A thousand shall fall at thy side - Though a thousand should fall at your side, or close to you. This alludes to the manner in which the pestilence often moves among people.

And ten thousand at thy right hand - Compare Psalms 3:6. The word "myriad" would better represent the exact idea in the original, as the Hebrew word is different from that which is translated "a thousand." It is put here for any large number. No matter how many fall around you, on the right hand and the left, you will have nothing to fear.

But it shall not come nigh thee - You will be safe. You may feel assured of the divine protection. Your mind may be calm through a sense of such guardianship, and your very calmness will conduce to your safety. This refers, as remarked above, to a "general" law regarding the judgments of God. It is true that others, besides the dissipated, vicious, and debased, may be the victims; but the great law is that temperance, soberness, virtue, cleanliness, and that regard for comfort and health to which religion and virtue prompt, constitute a marked security—so marked as to illustrate the "general" law referred to in the psalm before us.