But touch his bone and his flesh That is, smite him, not slightly, but to the quick, to the bones and marrow, so that he may feel pain and anguish indeed: and he will curse thee to thy face Will openly and daringly blaspheme thy perfections, and reproach the dispensations of thy providence, and so will let go his integrity. Satan knew, and we find by experience, that nothing has a greater tendency to ruffle the mind, and put its passions into disorder, than acute pain and distemper of body.
Related Commentaries of Job 2:5
Job 2:5
5 But put forth thine hand now, and touch his bone and his flesh, and he will curse thee to thy face.