cutting off the nose to spite the face
Definition:  doing something to hurt others, without considering that you might feel the pain as well
Usage:  the manager refused to pay his employees’ increase, consequently they downed the tools; he then realised that he was cutting off the nose to spite the face

SEPEDI
Translation:  go ripa nko, go swina sefahlego
Proverb: sehlola go hlola sa kgomo sa motho se a itlholela

XITSONGA
Translation:  ku tsema nhompfu u lava ku khanya xikandza
Proverb: u nga dungi xihlovo loko u heta ku nwa mati

TSHIVENḒA
Translation:  u ṱhukhula ningo hu u ṱoḓa u vhaisa tshifhaṱuwo
Proverb: a u vhulahi phondi nga u nwa mulimo