The spiritual function of fierce terrain (in the apophatic tradition) is to bring us to the end of ourselves, to the abandonment of language and the relinquishment of ego. A vast expanse of jagged stone, desert sand, and towering thunderheads has a way of challenging all the mental constructs in which we are tempted to take comfort and pride, thinking we have captured the divine. The things that ignore us save us in the end.
God is the friend of silence. See how nature -- trees, flowers, grass -- grow in silence; see the stars, the moon, the sun, how they move in silence... The more we receive in silent prayer, the more we can give in our active life. We need silence to be able to touch souls. The essential thing is not what we say, but what God says to us and through us. All our words will be useless unless they come from within.