David M CrumpDavid M. Crump is a former pastor and retired professor of New Testament at Calvin University in Grand Rapids, Michigan. He is the author of a number of books, including Knocking on Heaven's Door: A New Testament Theology of Petitionary Prayer(2006), Encountering Jesus, Encountering Scripture (2013), and I Pledge Allegiance: A Believer's Guide to Kingdom Citizenship in 21st Century America (2018). He blogs regularly at HumanityRenewed.com. Read More Read Less