Answer:
The theological teaching that states that the church and the state are two separate spheres is the Two Kingdoms Doctrine.
Step-by-step explanation:
The Two Kingdoms Doctrine is a Protestant Christian doctrine according to which God rules in the worldly kingdom through secular government by means of laws, and God also rules in the heavenly kingdom through the gospel and grace. This doctrine is held by Lutherans and Calvinists though other religious branches like Roman Catholics have similar views like the "two swords" doctrine.