《管子·形势解》
不应该再说的错话，这种话没有信用；不应该再做的错事，这种事害人至深。
言之不可复者，其言不信也；行之不可再者，其行贼暴也。
The wrong words that should not be repeated again are the kind that lack credibility; the wrong deeds that should not be repeated again are the ones that harm people the most.