Just as faith is the authentic force in the Kingdom of God, the world has illegitimate forces that seek to work against belief. Ungodly passion, lust,envy, greed and other carnal impulses seek to drown out faith and to undermine belief.
Faith is a force. Belief is a force. Faith's force is related to "epistes" which is 'trust'. We as believers are defined by our trust in God and God's opinion.