Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
In this case we shall not have two separate questions, namely, whether every foreigner who goes up on the wall is liable to the penalty, and whether this particular foreigner is liable, since no more forcible argument can be brought against the application of the letter of the law than the fact in dispute, but the only question to be raised will be whether a foreigner may not go on to the wall even for the purpose of saving the city. Therefore we shall rest our case on equity and the intention of the law. It is, however, sometimes possible to draw examples from other laws to show that we cannot always stand by the letter, as Cicero did in his defence of Caecina.
The third method becomes operative when we find something in the actual words of the law which enables us to prove that the intention of the legislator was different.
Anyone who is caught at night with steel in his hands shall be thrown into prison. A man is found wearing a steel ring, and is imprisoned by the magistrate.In this case the use of the word caught is sufficient proof that the word steel was only intended by the law in the sense of a weapon of offence.