Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
For there is scarce a single day in our lives that is so full of occupations that we may not, at some moment or other, snatch a few precious minutes, as Cicero [*](Or. 34. ) records that Brutus was
I must also mention the precept (which again has the approval of Cicero [*](There is no trace of this.) ) that we should never be careless about our language. Whatever we say, under whatever circumstances, should be perfect in its way. As regards writing, this is certainly never more necessary than when we have frequently to speak extempore. For it maintains the solidity of our speech and gives depth to superficial facility. We may compare the practice of husbandmen who cut away the uppermost roots of their vines, which run close to the surface of the soil, that the taproots may strike deeper and gain in strength.
Indeed I am not sure that, if we practise both with care and assiduity, mutual profit will not result, and writing will give us greater precision of speech, while speaking will make us write with greater facility. We must write, therefore, whenever possible; if we cannot write, we must meditate: if both are out of the question, we must still speak in such a manner that we shall not seem to be taken unawares nor our client to be left in the lurch.