“In either case the orator should bear clearly in mind throughout his whole speech what the fiction is to which he has committed himself, since we are apt to forget our falsehoods, and there is no doubt about the truth of the proverb that a liar should have a good memory.”
Book IV, Chapter II, 91; translation by H. E. Butler
Compare: "Liars ought to have good memories", Algernon Sidney, Discourses on Government, chapter ii, section xv.
Alternate translation for "solent excidere quae falsa sunt": False things tend to be forgotten
De Institutione Oratoria (c. 95 AD)
Original
Vtrubique autem orator meminisse debebit actione tota quid finxerit, quoniam solent excidere quae falsa sunt: verumque est illud quod vulgo dicitur, mendacem memorem esse oportere.
Help us to complete the source, original and additional information
Quintilian 18
ancient Roman rhetor 35–96Related quotes

To Leon Goldensohn, April 6, 1946, from "The Nuremberg Interviews" by Leon Goldensohn, Robert Gellately - History - 2004

Mont Saint Michel and Chartres (1904)

Want strong and happy marriage? This bishop gave BEST marriage advice ever! https://www.tuko.co.ke/230842-want-strong-happy-marriage-this-bishop-gave-best-marriage-advice-photo.html ()
Joshua G. Fitch. The art of questioning https://archive.org/stream/artofquestioning00fitcrich#page/n7/mode/2up. 9th edition. Published 1879. pp. 78-79

“A good liar must have a good memory. Kissinger is a stupendous liar with a remarkable memory.”
[The Trial of Henry Kissinger, 2002, 1859846319, 46240330, [E840.8.K58 H58 2001]]
2000s, 2002

Galen, On the Doctrines of Hippocrates and Plato,: PHP III 8.35.1-11 translation: De Lacy, Phillip (1978- 1984) Galen, On the Doctrines of Hippocrates and Plato, Berlin. p. 233; cited in: Christopher Jon Elliott. "Galen, Rome and the Second Sophistic." p. 147-8.

“A Judge must bear in mind that when he tries a case he is himself on trial.”
Special Laws, 1st century.

Hagakure (c. 1716)
Context: It is not good to settle into a set of opinions. It is a mistake to put forth effort and obtain some understanding and then stop at that. At first putting forth great effort to be sure that you have grasped the basics, then practicing so that they may come to fruition is something that will never stop for your whole lifetime. Do not rely on following the degree of understanding that you have discovered, but simply think, "This is not enough."
One should search throughout his whole life how best to follow the Way. And he should study, setting his mind to work without putting things off. Within this is the Way.