bìng cóng kǒu rù，huò cóng kǒu chū
Character To Character translation
: illness-from-mouth-enter, disaster-from-mouth-come out
: Disease enters by the mouth and trouble comes out of the mouth; mind your words
: mind your Ps and Qs // Think before you speak.
Búyào dāngzhòng suíbiàn fābiǎo pínglùn，~。
: Don’t comment casually in public. Mind your words.