Jesus presents us in the gospel the law of retaliation in Matthew 5:38: "You have heard that it was said: Eye for eye, and tooth for tooth".The law of the talion belongs to one of the old laws of the Hamurabi Code and is a clear case of practical application of Justice.
Aristotle defines Justice as "giving and receiving proportionally." Although it is present in the Old Testament, the promulgation of the 10 commandments by Moses represents an advance against the Code of Hamurabi, that is, the Law of Moses has as one of its aims to replace the old Babylonian Law.
In practical terms, the law of retaliation exposes the practical problem of the application of justice, although Aristotle explains that justice is general friendship and that the goal of justice is to maintain equality before the society, about justice affirms that vice can to pass as virtue, for example, rigor can be shown as Justice; in certain cases the application of this law can be a form of rigor. Plato also tells us about a problem with the application of this Law: "there is no greater injustice than to appear just without being". Justice in certain cases can be a mask. The law of talion for its exposure and simplicity presents us this problem.
That is why Jesus rejects this law as an insufficiency with the mercy and holds:"But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also. And if anyone wants to sue you and take your shirt, hand over your coat as well. If anyone forces you to go one mile, go with them two miles. Give to the one who asks you, and do not turn away from the one who wants to borrow from you", Matthew 5:39-42.
Jesus tells us that those who live according to the spirit are exempt from the fulfillment of the Law. Jesus carries all the human actions resume in the mercy (kindness, affability, benevolence). The beatitude and in this case the mercy are the best and what exceeds all human law.