Vicious habits are so great a stain to human nature, and so odious in themselves, that every person actuated by right reason would avoid them, though he were sure they would be always concealed both from God and man, and had no future punishment entailed upon them.
Marcus Tullius CiceroWho doesn't know that the first law of history is not to dare to say anything false, and the second is not to refrain from saying anything true?
Marcus Tullius CiceroThere is in fact a true law namely right reason, which is in accordance with nature, applies to all men and is unchangeable and eternal. ... It will not lay down one rule at Rome and another at Athens, nor will it be one rule today and another tomorrow. But there will be one law eternal and unchangeable binding all times and upon all peoples.
Marcus Tullius CiceroThe man who backbites an absent friend, nay, who does not stand up for him when another blames him, the man who angles for bursts of laughter and for the repute of a wit, who can invent what he never saw, who cannot keep a secret -- that man is black at heart: mark and avoid him.
Marcus Tullius Cicero