害人之心不可有，防人之心不可无
hài​rén​zhī​xīn​bù​kě​yǒu, fáng​rén​zhī​xīn​bù​kě​wú

vigilant kindness

害人之心不可有，防人之心不可无 (害人之心不可有，防人之心不可無) hài​rén​zhī​xīn​bù​kě​yǒu, fáng​rén​zhī​xīn​bù​kě​wú
vigilant kindness
refrain from hurting others, yet guard against those trying to hurt you

Sources
Definitions
CC-CEDICT