Who — He proceeds to give evidence of the Divine power and wisdom. Removeth — Suddenly and unexpectedly. They — The mountains, to which he ascribes sense and knowledge figuratively. In anger — In token of his displeasure with the men that live upon them.
Related Commentaries of Job 9:5
Job 9:5
5 Which removeth the mountains, and they know not: which overturneth them in his anger.