Which passage from the U.S. Constitution reflects the principle of federalism?

The Tenth Amendment of the U.S. Constitution reflects the principle of federalism by stating that powers not delegated to the federal government nor prohibited to the states are reserved to the states or the people. This delineation of authority reinforces the division of power between the national and state governments, highlighting the dual sovereignty that characterizes federalism. Additionally, Article I, Section 8 outlines the specific powers of Congress, further establishing the framework for federal authority while implicitly reserving other powers for the states.