It is error for any judge in any criminal case, during its progress or in his charge to the jury, to express or intimate his opinion as to what has or has not been proved or as to the guilt of the accused. Should any judge violate this Code section, the violation shall be held by the Supreme Court or Court of Appeals to be error and the decision in the case reversed, and a new trial granted in the court below with such directions as the Supreme Court or Court of Appeals may lawfully give.