The New Testament
"The Word of God, which is the power of God for salvation to everyone who has faith, is set forth and displays its power in a most wonderful way in the writings of the New Testament" which hand on the ultimate truth of God's Revelation. Their central object is Jesus Christ, God's incarnate Son: his acts, teachings, Passion and glorification, and his Church's beginnings under the Spirit's guidance.
Source: Catechism of the Catholic Church (Vatican.va)