He cutteth out rivers among the rocks - That is, in his operations of mining, he cuts channels for the water to flow off through the rocks. This was done, as it is now, for the purpose of drawing off the water that accumulates in mines.
His eye seeth every precious thing - Every valuable mineral or precious stone that lies imbedded in the rocks. It is evident from this, that mining operations were carried to a considerable extent in the time of Job. The art of thus penetrating the earth, and laying open its secret treasures, indicate an advanced stage of society - a stage much removed from barbarism.