Deuteronomy 19:21 in the King James Version
And thine eye shall not pity; but life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot.
Context
20 Those who remain shall hear, and fear, and will never again commit any such evil among you.
21 Your eyes shall not pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot.