Donald Carson is one of Strobel's expert witness in the Case for Christ. He holds a bachelor of science degree, but is also a research professor of New Testament who speaks 12 languages. He has authored or edited 40 books on the New Testament including: The Sermon on the Mount; Exegetical Fallacies; The Gospel according to John; and The Gagging of God, but his expertise lies in the areas of the historical Jesus and Greek grammar.