For he knoweth vain men - He is intimately acquainted with the heart; he knows human beings altogether. The word “vain” here (שׁוא shâv'), means properly vanity, emptiness, falsehood, a lie, iniquity. “Men of vanity,” here may mean people whose opinions are valueless, or it may mean people of deceit, falsehood, hypocrisy. Most probably it means the latter, and the indirect reference may be to such men as Job. The sense is, that God is intimately acquainted with such men. They cannot deceive him, and their wickedness will be found out.
Will he not then consider it? - Various ways have been proposed of explaining this. By some it is supposed to mean, “He seeth iniquity, where they do not observe it;” that is, he perceives it, where people do not themselves. This would express a thought which would accord well with the connection, but it is doubtful whether the Hebrew will bear this construction. By another explanation it is supposed to mean, as in our common version, “Will not God observe it, and bring it to trial? Will he suffer it to pass unnoticed?” This makes good sense, and the Hebrew will admit of this interpretation. But there is another view still, which is preferable to either. According to this it means, that God perceives the iniquity in man, though he does not seem to notice it; see the notes at Job 11:6. He appears to pass over a part of it, but he sees it notwithstanding, and is intimately acquainted with all the depravity of the heart. The main reference here is to Job, and the object is to show him that he was guilty, though he had asserted his innocence in so decided a manner. Though he seemed to himself to be innocent, yet Zophar labors to show him that he must be guilty, and that he had seen but a small part of his sins.