Our security is in the favour of God alone!
Mountain is symbolic of God's favour
"He speaks of himself as having, through the favor of God, put himself into a strong position - a position where he feared no enemy and no change; where he thought himself entirely secure - the state of "prosperity" to which he had referred in the previous verse. In that state, however, God showed him that there was no real security but in his favor: security not in what a man can draw around himself, but in the favor of God alone."
~Barnes' Notes on the Bible (commentary)
