Charles Ellicott Commentary Job 12:9

"Who knoweth not in all these, That the hand of Jehovah hath wrought this," — Job 12:9 (ASV)

Who knoweth not in all these that the hand of the Lord hath wrought this? (Job 12:9) — This is the only place in the dialogue parts of Job where the sacred name of Jehovah is found, and Job's use of the word itself in such a context is the clearest evidence of the superior knowledge he claims. None of his friends use the name; but Job uses it here, and by this shows his knowledge of the covenant name.