Which removeth the mountains, and they know not: which overturneth them in his anger.
And they know not - Hebrew for 'suddenly; unexpectedly; before they are aware of it;' "at unawares" (Psalms 35:8) - Hebrew, which he knoweth not of.
Related Commentaries of Job 9:5
Job 9:5
5 Which removeth the mountains, and they know not: which overturneth them in his anger.