Institutio Oratoria

For since the case turns on the propounding and refutation of arguments, it is always possible to write out what we propose to advance on our own behalf, and similar preparation is also possible with regard to the refutation of such replies as are absolutely certain to be made by our adversary: for there are times when we have this certainty. But with regard to all other portions of our speech, the only preparation that is possible in advance consists in a thorough knowledge of our case, while there is a second precaution which may be taken in court, consisting in giving our best attention to our opponent's speech.