Why does the church not have the impact on society it should?

Ravi Zacharias in his book, Deliver us from Evil, a book we picked up at a Christian second hand book shop in Erith, when we were waiting for Andrew Kruse's wedding, deals with the cause of why the church has lost it's influence in a secular world that has become very anti-God. Quoting the Canadian Historian, David Marshall he says, "From their ranks [the clergy] came the call to congregations to abandon the notion of an authoritative Scripture and surrender the biblical perspective on life's deepest questions." (p.51) When we give up on the authority of Scripture, we lose a power to influence because the standard by which we govern our lives now becomes human based, rather than God based. When it is human based, then anyone can say that his idea of what is good and right is just as good and right as someone else's idea. This is the consequence of giving up on the authority of God's word. This is what we as a Christian community face, and we need to give God's word a greater respect in our lives, and allow God to be our God in every choice and decision we make.