As a scholar, he is internationally known for his studies of John's Gospel, the book of Revelation, and the Epistle to the Hebrews.
As a teacher he is known for his innovative use of music and visuals to engage students in the study of the New Testament.
He currently serves as Academic Dean at Luther Seminary
In 2014 he published a commentary on Revelation in the prestigious Anchor Yale Bible series. It is the culmination of a decade of work and explores the many facets of Revelation's context, literary qualities, and history of interpretation. He reads Revelation as a text that both challenges and encourages. He understands Revelation to be a world-engaging text, which portrays God as Creator and Jesus as the redeeming Lamb. It is a reference work that invites readers into the the interpretive process.