Members of the General Assembly, and all officers, before they enter upon the duties of their respective offices, and all members of the bar, before they enter upon the practice of their profession, shall take and subscribe the following oath: "I do solemnly swear (or affirm) that I am duly qualified, according to the Constitution of this State, to exercise the duties of the office to which I have been elected, (or appointed), and that I will, to the best of my ability, discharge the duties thereof, and preserve, protect, and defend the Constitution of this State and of the United States. So help me God."