Pennsylvania constitution
Article VI: public officers
Section 3

Senators, Representatives and all judicial, State and county officers shall, before entering on the duties of their respective offices, take and subscribe the following oath or affirmation before a person authorized to administer oaths. "I do solemnly swear (or affirm) that I will support, obey and defend the Constitution of the United States and the Constitution of this Commonwealth and that I will discharge the duties of my office with fidelity." The oath or affirmation shall be administered to a member of the Senate or to a member of the House of Representatives in the hall of the House to which he shall have been elected. Any person refusing to take the oath or affirmation shall forfeit his office.