The Westminster Shorter Catechism, Question 78.
Q. 78. What is forbidden in the ninth commandment?
A. The ninth commandment forbiddeth whatsoever is prejudicial to truth, or injurious to our own, or our neighbor’s good names.
Whatsoever is prejudicial to truth. –Every thing that is opposite, or contrary, or hurtful to the truth; such as, lying, flattery, dissimulation, &c.
Whatsoever is injurious to our own good name. –Every thing that is hurtful to our own character in the world; such as, sinful and imprudent speech, and improper conduct of every kind.
Whatsoever is injurious to our neighbor’s good name. –Every thing that may hurt the character of our neighbor among men; such as, speaking evil of those who, we think, may have done us wrong, taking pleasure to make known the real faults of another, and such like.
The sins forbidden in the ninth commandment, are three-fold:
- Whatsoever is prejudicial to truth. –Rom. iii. 13. With their tongues they have used deceit. Col. iii. 9. Lie not one to another.
- Whatsoever is injurious to our own good name. –Job xxvii. 5. God forbid that I should justify you; till I die, I will not remove my integrity from me.
- Whatever is injurious, or hurtful, to the character of our neighbor. –Psalm xv. 3. He that backbiteth not with his tongue, nor doth evil to his neighbor, nor taketh up a reproach against his neighbor. Exodus xxiii. 1. Thou shalt not raise, or receive, a false report.