Shameless men are wont by lying to deny their guilt when they have been found out.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic guilt lie
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/18755/pg18755-images.html

Context

“He who lies in court by denying his guilt, acts both against the love of God to whom judgment belongs, and against the love of his neighbor, and this not only as regards the judge, to whom he refuses his due, but also as regards his accuser, who is punished if he fail to prove his accusation. Hence it is written (Ps. 140:4) : "Incline not my heart to evil words, to make excuses in sins": on which words a gloss says: "Shameless men are wont by lying to deny their guilt when they have been found out." And Gregory in expounding Job 31:33, "If as a man I have hid my sin," says (Moral. xxii, 15) : "It is a common vice of mankind to sin in secret, by lying to hide the sin that has been committed, and when convicted to aggravate the sin by defending oneself."” source