Impassibility and revelation

What is the relation between divine unchangeability and the reality of change as implied in ideas of creation and redemption? Western Trinitarian theology in the 20^th century tended toward emphasizing the significance of change above divine unchangeability, giving it a modalist and Hegelian flavour that questioned the continuity with the church fathers. For this reason, it has been criticized by Orthodox theologians like Vladimir Lossky and David Bentley Hart. Newer scholarship has shown the significance of Luther's appropriation of the doctrine of divine unknowability and his insistence on the difference between revelation and divine essence for his understanding of the Trinity, which thus may appear to be much closer to the position of the Orthodox critics than to the Lutheran theologians criticized by them. There thus seems to be an unused potential in Luther's doctrine of the Trinity that should be of interest both for systematic and ecumenical theology.