Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
is not wholly unreasonable. Still no one should interpret it to mean that you must stop short of nothing. For the Greeks are right when they lay it down as a rule that we should not attempt the impossible. But whenever the double-barrelled defence of which I am speaking is employed, we must aim at making the first argument support the credibility of the second. For he who might without danger to himself have confessed to the commission of the act, can have no motive for lying when he denies the commission.
Above all it is important, whenever we suspect that the judge desires a proof other than that on which we are engaged, to promise that we will satisfy him on the point fully and without delay, more especially if the question is one of our client's honour.