Which amendment in the Bill of Rights promises this liberty? The powers not delegated to the United States by constitution nor prohibited by it to the states, or a reserved to states respectively or to the people.

The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people. The Tenth Amendment was included in the Bill of Rights to further define the balance of power between the federal government and the states.