U.S. Constitution, Article I — The Legislative Branch, Section 6, Clause 1
The Senators and Representatives shall receive a Compensation for their Services, to be ascertained by Law, and paid out of the Treasury of the United States. They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place.
Notes
Requires members of Congress to be paid a compensation set by law out of the Treasury of the United States, bars their arrest while attending or traveling to and from sessions except for treason, felony and breach of the peace, and bars questioning them anywhere else over any speech or debate in either house.
Use as reference
Lexinter.net | U.S. Const. art. I, § 6, cl. 1 | https://laws.lexinter.net/constitution/us/article-1/section-6/clause-1