Marcus Borg argues that meeting Jesus challenges Christians to move from a secondhand religion to a firsthand religion. 
"Secondhand religion is a way of being religious based on believing what one has heard from others. It consists of thinking that the Christian Life is about believing what the Bible says or what doctrines of the church say." — Marcus Borg
"Firsthand religion, on the other hand, consists of a relationship to that which the Bible and the teachings of the church point—namely, that reality that we call God or the Spirit of God." — Marcus Borg
These quotes from Marcus Borg's book, "Meeting Jesus for the first time" pp. 87-8 are a helpful explanation of why Karl Barth's reorientation upon Jesus as the revelation of God is so important.
According to Karl Barth, the bible is a human witness to Jesus whom is the revelation of God. Barth improves upon Borg by seeing Jesus as the firsthand revelation of God and abolishing all religions that point to a holy book or religious organization.
A bible-believing church is an example of secondhand religion wherein the Bible has replaced Jesus as an object of faith and results in idolatry of the Bible. Another example is inerrancy that obsesses upon the purity of human tradition texts.
