We act against evil, against those forces that corrupt life. We live actively and dynamically against spiritual disease. Salt can also lose its usefulness. Instead of bringing out the full flavor of the Christian life, the professed Christian can dull the taste of life. We can live in a way that fails to meet people's needs.
Poor lawyers make poor mediators for their clients.
Poor physicians make poor instruments for healing people. Poor Christians are poor influences, poor keeper's of the truth, poor in acting against those forces that corrupt life. Christ meant our lives to count. So much of life is stale and flat for many people, unprofitable and useless. So much of life is futile.