Deuteronomy 19:21
And thine eye shall not pity; but life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot. And thine eye shall not pity; but life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot.
The verse lays down the principle of proportionate justice, requiring that the penalty correspond to the injury and not exceed it, with pity allowed to change nothing in that measure. It is stated as the rule of reciprocal punishment, an eye for an eye and a tooth for a tooth. It gives equal justice, life for life, eye for eye, tooth for tooth, hand for hand, foot for foot.
Jesus set this legal rule over against the desire to turn it into a justification for personal revenge. He taught His followers not to use it to retaliate for personal wrongs and not to resist evil by revenge. They are not to answer oppression with hatred, but to endure insults and oppression without revenge. Instead they are to answer injury with patience, generosity and kindness, even meeting demands with generosity.