 Heiler never completely abandoned his Roman Catholic faith, but developed further the idea of "Evangelical Catholicity" based on Augsburg Confession from his own liberal Catholic point of view.He, for example, did not approve the traditional Lutheran doctrine of forensic justification.Heiler favored Franciscan spirituality and he influenced the foundation of Lutheran Franciscan Third Order (Evangelische Franziskaner-Tertiaren) 1927 within Hochkirchliche Vereinigung.