Each judicial officer shall, before entering on the duties of his office, 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."
Any person refusing to take the oath or affirmation shall forfeit his office. A judicial officer shall be sworn upon his appointment or election, and after each retention election, and thereafter need not be sworn in any matter referred to him.