Mascall and Barth shared a common concern with the influence of liberal Protestantism on their churches in England and Germany. They agreed this problem was best addressed through the lens of natural theology. Yet, while for Mascall a Thomistically informed understanding of natural theology was the best way to counteract liberal Protestantism’s influence on the Church, for Barth, natural theology was to blame for the Church’s confusion. Was Barth’s sharp delineation between human reason and divine revelation in the end, complicit with the ontological duality of modernity that was the basis of the liberal Protestantism he was rejecting? Dealing with modernity on its own terms, Barth undermined the capacity of the Church’s ministry of Word and Sacrament to be effective agents of personal transformation. Whereas Mascall’s realistic ontology not only repudiates the idealist foundations of liberal Protestantism, it also offers the Church the necessary ontological foundation for understanding its ministry of Word and Sacrament as effective embodiments of God’s transforming grace.