Jamieson, Fausset and Brown on Job 35:5-8

5-8. Elihu like Eliphaz (Job 22:2, 3, 12) shows that God is too exalted in nature to be susceptible of benefit or hurt from the righteousness or sin of men respectively; it is themselves that they benefit by righteousness, or hurt by sin.

behold the clouds, which are higher than thou--spoken with irony. Not only are they higher than thou, but thou canst not even reach them clearly with the eye. Yet these are not as high as God's seat. God is therefore too exalted to be dependent on man. Therefore He has no inducement to injustice in His dealings with man. When He afflicts, it must be from a different motive; namely, the good of the sufferer.