Job 33:3

My words shall be of the uprightness of my heart - I will speak in sincerity. I will utter nothing that shall be hollow and hypocritical. What I speak shall be the real suggestion of my heart - what I feel and know to be true. Perhaps Elihu was the more anxious to make this point entirely clear, because the three friends of Job might be supposed to have laid themselves open to the suspicion that they were influenced by passion or prejudice; that they had maintained their opinions from mere obstinacy and not from conviction; and that they had been sometimes disposed to cavil. Elihu claims that all that he was about to say would be entirely sincere.

Shall utter knowledge clearly - Shall state things just as they are, and give the true solution of the difficulties which have been felt in regard to the divine dealings. His object is to guard himself wholly from the suspicion of partiality.