I have seen the foolish, &c.— I saw the profligate taking root, but I marked him out for sudden destruction. This is the same thought as in Psalms 37:35-36 and drawn out at length in Psalms 73. See Heath and Schultens.
Related Commentaries of Job 5:3
Job 5:3
3 I have seen the foolish taking root: but suddenly I cursed his habitation.