If I speak of strength, lo, he is {n} strong: and if of judgment, who shall set me a time to plead?

(n) After he has accused his own weakness, he continues to justify God and his power.

Wesley's Notes

9:19 If - If my cause were to be decided by power. Is Strong - Stronger than I. Judgment - If I would contend with him in a way of right. Who - There is no superior judge that can summon him and me together.

Jamieson-Fausset-Brown Bible Commentary

19. Umbreit takes these as the words of God, translating, "What availeth the might of the strong?" "Here (saith he) behold! what availeth justice? Who will appoint me a time to plead?" (So Jer 49:19). The last words certainly apply better to God than to Job. The sense is substantially the same if we make "me" apply to Job. The "lo!" expresses God's swift readiness for battle when challenged.

Matthew Henry's Concise Commentary

9:14-21 Job is still righteous in his own eyes, ch. 32:1, and this answer, though it sets forth the power and majesty of God, implies that the question between the afflicted and the Lord of providence, is a question of might, and not of right; and we begin to discover the evil fruits of pride and of a self-righteous spirit. Job begins to manifest a disposition to condemn God, that he may justify himself, for which he is afterwards reproved. Still Job knew so much of himself, that he durst not stand a trial. If we say, We have no sin, we not only deceive ourselves, but we affront God; for we sin in saying so, and give the lie to the Scripture. But Job reflected on God's goodness and justice in saying his affliction was without cause.