[Luke 1:1-4] Twelve Apostles were chosen as faithful eyewitness of the Old Testament fulfillment in their midst. Islam and Mormonism stand in opposition to this as unverifiable, secret revelation claimed by one man. Creation is our apologetic for God, but the Old Testament is our apologetic for Jesus. 
The Spirit and the Word together is the guarantee of truth; personal experience of objective truth is the Holy Spirit illuminating God’s Word.