23. What is the unity that exists between the Old and the New Testaments?
Scripture is one insofar as the Word of God is one. God's plan of salvation is one, and the divine inspiration of both Testaments is one. The Old Testament prepares for the New and the New Testament fulfills the Old; the two shed light on each other.
Further reading: CCC 128-130, 14024. What role does sacred scripture play in the life of the Church?
Sacred Scripture gives support and vigor to the life of the Church. For the children of the Church, it is a confirmation of the faith, food for the soul and the fount of the spiritual life. Sacred scripture is the soul of theology and of pastoral preaching. The Psalmist says that it is "a lamp unto my feet and a light to my path." (Psalm 119:105). The Church, therefore, exhorts all to read Sacred Scripture frequently because "ignorance of the Scriptures is ignorance of Christ" (Saint Jerome).
Further reading: CCC 131-133, 141-142