Article I of the Constitution defines the role of Congress, the federal legislative branch. Section 1 gives legislative powers to a bicameral Congress. Section 2 defines the roles and responsibilities of the House of Representatives; Section 3 defines the powers of the Senate.
The following was prepared by the Office of the Secretary of the Senate with the assistance of the Library of Congress, providing the original text of each clause of the Constitution with an accompanying explanation of its meaning and how that meaning has changed over time. Source: U.S. Senate, Library Of Congress