But I would strengthen you with my mouth. The meaning is somewhat doubtful, and different renderings have been proposed. But the rendering of the Authorized Version is quite defensible, and is accepted by our Revisers.
This gives the sense, "I, if I were in your place, would not act as you have acted, but, on the contrary, would do my best to strengthen you with words of comfort and encouragement." The moving of my lips should assuage your grief.
(So Rosenmuller and our Revisers.) The words are a covert reproach of the three "friends" for not acting as Job declares that he would have acted if the positions had been reversed.