Precaution in bloods and its application in criminal law

Abstract
Many of the provisions in the Islam is legislation to protect the human lives. This is Indicative the special importance of saving lives in front of God. But what is not clear in this regard, it is with this degree of importance of human life in Islam, why is there many the death penalty in this religion? This penalty Indeed, with such a good record in Islamic societies are correct and based on the teachings of Islam?
In order to answer the above questions we have to examine the evidence Ejtehadi. Studying the Quran and the Sunnah and the Islamic viewpoint on the death penalty achieved the famous principle of precaution in bloods.
According to the precaution in bloods’, legislation and implementation of the death penalty should be documented because of certain or circumstantial evidence and in other cases you have to be cautious and sentencing and in execution of the death penalty, avoided without certainty reason.
But this rule has not been independently investigate. The authors of this research, exploration of reasons, principles and scope of it, have noted to the Penal Code Act of 1392 and other criminal law that is inconsistent with this rule.