Biblical theology, as a discipline, seeks to understand the Bible in its historical context, its progressive revelation, and its unity across both the Old and New Testaments. New Testament Biblical Theology is concerned specifically with the theology as it is presented in the New Testament writings, which include the four Gospels, the Acts of the Apostles, the letters of the Apostle Paul, and other epistolary writings, as well as the apocalyptic literature found in the Book of Revelation. The New Testament is primarily concerned with the revelation of God in Jesus Christ, and the development of early Christian thought in response to His life, death, and resurrection.