Book Seventh. On the Eighth Precept of the Decalogue

¹ "You shall not speak false testimony against your neighbor." Ex. 20:16.

This precept, insofar as it is negative, prohibits primarily false testimony, whether in judgment or outside judgment; secondarily, however, it prohibits lying and the unjust lesion of the reputation and honor of one's neighbor which is done by words. But insofar as it is affirmative, it commands that we always speak the truth. Therefore by this precept generally it is prohibited that damage be inflicted on one's neighbor by words or equivalent signs. Wherefore one must treat: a. of veracity and fidelity; b. of lying; c. of detraction; d. of insult; e. of violation of a secret.

Although violation of a secret can harm one's neighbor not only in the goods of reputation and honor, but also in goods of life and fortune, and therefore can also be opposed to the fifth and seventh precept, nevertheless authors are accustomed to refer the treatment of it to the eighth precept.

¹ St. Thomas II-II, q. 72-74; St. Alphonsus, l. 3, n. 962-1003; Lugo, De iustitia et iure, disp. 14; Tamburini, Explicatio decalogi, l. 9; Reuter, Theologia moralis II, n. 395-432; Sporer-Bierbaum, Theologia moralis decalogalis II, tract. V, n. 630-776; Ballerini-Palmieri, Opus Theolog. moral. II, n. 1050-1102; Lehmkuhl, Theologia moral.^10 I, n. 1172-1200; Genicot, Theologiae moralis institut.^3 I, n. 412-433.