Will you speak falsely for God and speak deceitfully for him?
Job here warmly expresses his resentment of the unkindness of his friends. I. He comes up with them as one that understood the matter in dispute as well as they, and did not need to be taught by them, Job 13:1, Job 13:2. They compelled him, as the Corinthians did Paul, to commend himself and his own knowledge, yet not in a way of self-applause, but of self-justification.
Commenting on Job 13:1-12
Will you speak wickedly for God?.... As he suggests they did; they spoke for God, and pleaded for the honour of his justice, by asserting he did not afflict good men, which they thought was contrary to his justice; but: then, at the same time, they spoke wickedly of Job, that he being afflicted of God was a bad man, and an hypocrite; and this...
deceitfully--use fallacies to vindicate God in His dealings; as if the end justified the means. Their "deceitfulness" for God, against Job, was that they asserted he was a sinner, because he was a sufferer.