To the first class belong the Gospels and Acts; to the second, the Epistles; to the third, the Revelation.

The quote "To the first class belong the Gospels and Acts; to the second, the Epistles; to the third, the Revelation" by Philip Schaff categorizes the various books of the New Testament based on their content and theological focus. Schaff, a renowned 19th-century church historian and theologian, offers a structured approach to understanding the diverse types of writings found in the Christian Bible. By dividing the New Testament into three categories, he seeks to highlight the distinct roles these texts play in the Christian faith.

In the first category, Schaff places the Gospels (Matthew, Mark, Luke, and John) and the Acts of the Apostles. These works primarily focus on the life, teachings, death, and resurrection of Jesus Christ and the early history of the Christian Church. The Gospels provide the foundation of Christian doctrine, while Acts gives insight into the early spread of Christianity and the work of the apostles, particularly Peter and Paul.

The second category, the Epistles, refers to the letters written by various apostles, particularly Paul, to early Christian communities or individuals. These letters provide theological teachings, moral guidance, and pastoral counsel. The Epistles are crucial for understanding Christian doctrine, ethics, and church organization, offering deeper theological reflections on the significance of Christ's life and resurrection for the believers.

Finally, Schaff places the Revelation (or Apocalypse) in the third class. The Revelation, written by the apostle John, is distinct in its prophetic and apocalyptic nature, offering visions of the ultimate victory of Christ over evil and the establishment of God's eternal kingdom. Schaff's classification highlights the Revelation's unique role in conveying the hope and future promises of the Christian faith, set apart from the other writings that focus more on historical events and practical teachings.

Through this categorization, Schaff provides a way of understanding the varied purposes of the New Testament texts, emphasizing their theological depth and the progression from historical narrative to doctrinal teaching, and finally, to the ultimate eschatological vision of the Christian hope.