an eye for an eye
From Longman Dictionary of Contemporary Englishan eye for an eyean eye for an eyeREVENGEthe idea that if someone does something wrong, you should punish them by doing the same thing to them An eye for an eye is no way to run a civilised justice system. → eyeExamples from the Corpusan eye for an eye• The Old Testament ideal of an eye for an eye speaks to that need.