Overview
"An eye for an eye" is a commandment found in the Book of Exodus 21:23–27 expressing the principle of reciprocal justice measure for measure. The earliest known use of the principle appears in the Code of Hammurabi, which predates the Hebrew Bible.
The law of exact retaliation, or reciprocal justice, bears the same principle that a person who has injured another person is to be penalized to a similar degree by the injured party. In softer interpretations, it means the victim receives the [estimated] value of the injury in compensation. The intent behind the principle was to restrict compensation to the value of the loss.
Definition and methods
The term lex talionis does not always and only refer to literal eye-for-an-eye codes of justice (see rather mirror punishment) but applies to the broader class of legal systems that specifically formulate penalties for specific crimes, which are thought to be fitting in their severity. Some propose that this was at least in part intended to prevent excessive punishment at the hands of either an avenging private party or the state. The most common expression of lex talionis is "an eye for an eye", but other interpretations have been given as well. Legal codes following the principle of lex talionis have one thing in common: prescribed 'fitting' counter punishment for a felony. The simplest example is the "eye for an eye" principle. In that case, the rule was that punishment must be exactly equal to the crime.
In Babylonian law
In the legal Code of Hammurabi, the principle of exact reciprocity is very clearly used. For example, if a person caused the death of another person, the killer would be put to death.
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