Unknown Author
Job 9:20ESV·author unknown

Though I am in the right, my own mouth would condemn me; though I am blameless, he would prove me perverse.

Matthew Henry Presbyterian @wholebiblehenry

What Job had said of man's utter inability to contend with God he here applies to himself, and in effect despairs of gaining his favour, which (some think) arises from the hard thoughts he had of God, as one who, having set himself against him, right or wrong, would be too hard for him.

Commenting on Job 9:14-21

John Gill Reformed Baptist @doctorgill

Though I were perfect,.... Really and truly so, not conscious of any sin in thought, word, or deed; this is only a case supposed: yet would I not know my soul; I would not own myself to be so before God; I would not insist upon such perfection in his presence, as what would justify me before him; since I am sensible the highest perfection...

Jamieson-Fausset-Brown Reformed @jfbcommentary

it-- (Job 15:6; Luk 19:22); or "He," God.