Faith is not an arbitrary idea. It is not passive. Faith is action! Faith requires a response. Faith is the continual movement, the constant pursuit of God and His will and the decision to step forward in obedience even when we do not understand.
Living by faith can be likened to walking on a treadmill. As long as you are moving forward, step by step, you remain on the treadmill, but the moment you stop moving you automatically begin to move backwards and eventually fall off.
Faith is calling us to action! We must choose to continually respond and move into the unknown trusting God to lead us step by step.