10 “Preparing mountains in His strength”. Not in their strength. For He has prepared great preachers, and those same He has called mountains; humble in themselves, exalted in Him. “Preparing mountains in His strength.” What says one of those same mountains? “We ourselves in our own selves have had the answer of death, in order that in ourselves we should not trust, but in God that raises the dead.” He that in himself does trust, and in Christ trusts not, is not of those mountains which He has prepared in His strength. “Preparing mountains in His strength: girded about in power.” “Power,” I understand: “girded about,” is what? They that put Christ in the midst, “girded about” they make Him, that is on all sides begirt. We all have Him in common, therefore in the midst He is: all we gird Him about that believe in Him: and because our faith is not of our strength, but of His power; therefore girded about He is in His power; not in our own strength.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)