The Vesting Clauses are provisions in Article I, Section 1; Article II, Section 1, Clause 1; and Article III, Section 1 of the United States Constitution. These vest the legislative, executive, and judicial powers in the Congress, President, and federal judiciary (the Supreme Court and the then-uncreated inferior courts), respectively. The Constitution thus explicitly creates a clear Separation of powers in the federal government.
Article I, Section 1:
All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives.
Article II, Section 1, Clause 1:
The executive Power shall be vested in a President of the United States of America. He shall hold his Office during the Term of four Years, and, together with the Vice-President chosen for the same Term, be elected, as follows:[...]
Article III, Section 1:
The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behavior, and shall, at stated Times, receive for their Services a Compensation which shall not be diminished during their Continuance in Office.