What knowest thou, that we know not? what understandest thou, which is not in us?

Jamieson-Fausset-Brown Bible Commentary

9. in us-or, "with us," Hebraism for "we are aware of."

Matthew Henry's Concise Commentary

15:1-16 Eliphaz begins a second attack upon Job, instead of being softened by his complaints. He unjustly charges Job with casting off the fear of God, and all regard to him, and restraining prayer. See in what religion is summed up, fearing God, and praying to him; the former the most needful principle, the latter the most needful practice. Eliphaz charges Job with self-conceit. He charges him with contempt of the counsels and comforts given him by his friends. We are apt to think that which we ourselves say is important, when others, with reason, think little of it. He charges him with opposition to God. Eliphaz ought not to have put harsh constructions upon the words of one well known for piety, and now in temptation. It is plain that these disputants were deeply convinced of the doctrine of original sin, and the total depravity of human nature. Shall we not admire the patience of God in bearing with us? and still more his love to us in the redemption of Christ Jesus his beloved Son?