The proper Protestant doctrine of the Two Kingdoms doesn’t identify the two kingdoms with the Church and the State. This is actually the papalist doctrine of the Two Swords wielded by the prince and the pope. The Two Kingdoms are properly the invisible church which is a spiritual communion of the faithful sharing from the heart the same faith, hope and love in Christ, and the visible realm which includes both the visible church and the state. Both visible church and state are under the reign of Christ where only in the former is there the Holy Ghost given through the preached Word received through faith.