But oh that God would speak - Hebrew, “and truly, who will give that God should speak.” It is the expression of an earnest wish that God would address him, and bring him to a proper sense of his ill desert. The meaning is, that if God should speak to him he would by no means find himself so holy as he now claimed to be.
Related Commentaries of Job 11:5
Job 11:5
5 But oh that God would speak, and open his lips against thee;