The 10 Commandments as a Basis for Morality?
9. Thou shalt not bear false witness.
- 16 Thou shalt not bear false witness against thy neighbour.
I could quibble a bit over exactly what is meant by "thy neighbour," but other than that, I really cannot challenge this particular commandment. Given the pernicious effects of lies, rumor and innuendo, this directive is as close to a moral absolute as you will get in few words.
Moral value of the ninth commandment: 10 / 10