Holy Scripture comprises the writings of both the New and the Old Testaments. The New Testament reveals the human and divine nature of Jesus Christ, and His sacred teachings that we are charged to follow. The Old Testament is a history of the Hebrew people. It contains, among other sacred writings, the prophecies and the writings of the Prophets that foretold the coming of the Messiah. It therefore serves as an introduction to the revelation and the saving message of the New Testament.
Holy Tradition, of which Holy Scripture is a part, includes the writings, teachings, and acts of the apostles, saints, martyrs, and fathers of the Church, and her liturgical and sacramental traditions throughout the ages, the oral tradition of the early Church, and the decisions of the Ecumenical Councils. All of this collective wisdom and experience through the centuries are combined to form this second great source of sacred authority.