 He was a frequent preacher on college campuses in the following decades and was asked to deliver the Stone Foundation Lectures at Princeton, the Smythe Lectures at Columbia Theological Seminary, and the Payton Lectures at Fuller Theological Seminary.He opposed the spread of neo-orthodoxy at Princeton Theological Seminary, questioning, for instance, the decision to hire Emil Brunner.He also mentored over a dozen assistant pastors, including Harold Ockenga, the founder of the National Association of Evangelicals.