Arnold received his B.A. from Biola College, completed his M.Div. at Talbot Theological Seminary, and did his Ph.D. at the University of Aberdeen under the supervision of I. Howard Marshall. His dissertation title was, "The Power of God and the Powers of Evil in the Epistle to the Ephesians." Arnold has done post-doctoral study at the University of Tübingen, Germany, on The Historical Context of the Epistle to the Colossians under Peter Stuhlmacher.