Servants — They are called his servants by way of eminency, that general name being here appropriated to the chief of the kind, to intimate that sovereign dominion which the great God hath over the angels, and much more over men. With folly — Without all doubt, this refers to those angels who foolishly and wickedly fell from God.
Related Commentaries of Job 4:18
Job 4:18
18 Behold, he put no trust in his servants; and his angels he charged with folly: