(a) Justices, judges and justices of the peace shall be compensated by the Commonwealth as provided by law. Their compensation shall not be diminished during their terms of office, unless by law applying generally to all salaried officers of the Commonwealth.

  (b) Justices, judges and justices of the peace shall be retired on the last day of the calendar year in which they attain the age of 70 years. Former and retired justices, judges and justices of the peace shall receive such compensation as shall be provided by law. Except as provided by law, no salary, retirement benefit or other compensation, present or deferred, shall be paid to any justice, judge or justice of the peace who, under section 18 or under Article VI, is suspended, removed or barred from holding judicial office for conviction of a felony or misconduct in office or conduct which prejudices the proper administration of justice or brings the judicial office into disrepute.

  (c) A former or retired justice or judge may, with his consent, be assigned by the Supreme Court on temporary judicial service as may be prescribed by rule of the Supreme Court.