Albert Barnes Commentary Job 36:5

"Behold, God is mighty, and despiseth not any: He is mighty in strength of understanding." — Job 36:5 (ASV)

Behold, God is Mighty - This is the first consideration that Elihu urges, and the purpose seems to be to affirm that God is so great that He has no occasion to modify His treatment of any class of people out of consideration for Himself. He is wholly independent of all and can therefore be impartial in His dealings. If it were otherwise—if He were dependent on human beings for any share of His happiness—He might be tempted to show special favor to the great and the rich, to spare the mighty who are wicked, though He cuts off the poor. But He has no such inducement, as He is wholly independent; and it is to be presumed, therefore, that He treats all impartially (see the notes on Job 35:5-8).

And despiseth not any - He despises no one who is poor and humble. He does not pass them by with cold neglect because they are poor and powerless, nor turn His attention to the great and mighty because He is dependent on them.

He is mighty in wisdom - (Margin: “heart.”) The word “heart” in Hebrew is often used to denote the intellectual powers, and the idea here is that God has perfect wisdom in the management of His affairs. He is acquainted with all the circumstances of His creatures and passes by no one from a defect of knowledge or a lack of wisdom to know how to adapt His dealings to their condition.