Precisely, faith. I choose not to encumber myself with historical accretions but will rely on God's word as revealed in scripture. All the rest is nothing more than barnacles encrusted on the hull of a ship.
Your own personal interpretation of scripture is of no use to me. I will stick with the Church founded by Christ and guided by the Holy Spirit to this very day, and the gates of hell shall not prevail against it. Those who want to settle for less, or whatever they want to make of the Gospel, they are on their own.
The Catholic Church is the Pillar and Ground of the Truth.
You don't even know what scripture is apart from the teaching of the Catholic Church. Who do you think collected the New Testament books and declared that they were inspired?
"I would not believe in the Gospel were it not for the authority of the Catholic Church" -- Augustine of Hippo.