Q. Does Judaism really teach “an eye for an eye” (Ex. 21:4)?
A. The lex talionis (“an eye for an eye”) is understood as requiring a criminal to pay compensation. It is not a primitive law of revenge whereby if you injured my eye, I injure yours. It also establishes that the compensation paid by a criminal is not affected by whether the criminal is a noble or the victim is a slave.
The law of capital punishment (seen as necessary on the statute book in order to highlight the gravity of offences such as bloodshed) was hardly ever applied. The sages of the Mishnah (Makkot 1:10) say that a court which imposes the death penalty is a bloodthirsty court.