The Seal of the Spirit: A Study in the Doctrine of Baptism and Confirmation in the New Testament and the Fathers by G.W.H. Lampe is a foundational academic, historical study exploring the theological relationship between the gift of the Holy Spirit, water baptism, and early church initiation rites. The work examines New Testament evidence and the writings of early Church Fathers to trace the development of baptism and confirmation doctrines. The book is known for its depth, incorporating extensive citations from Greek and Latin sources offering a critical look at whether confirmation is an essential, separate, and obligatory complement to baptism.