The Fourteenth Amendment (Section 1):

All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.  No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
 

Related Provisions

Privileges and Immunities Clause of Article IV, Section 2:

The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in the several States.

Due Process Clause of Amendment V:

No person shall be...deprived of life, liberty, or property, without due process of law.