The rule of the most important and the important in duress to Homicide

Duress is one of the factors that, according to the Hadith of Raf and other reasons, eliminate duty and responsibility from committing a crime but well-known Imams' jurists accepted duress in homicide and are believed that in the case of committing, the person becomes the retribution. The main question of this study is that, with Supposing the acceptance of the famous opinion, Whenever a threat comes from Mokrah, is more important and more difficult than homicide that Mokrah duress to that, for example a person duress other to homicide a person and Threatening if he don’t homicide him, he will homicide the whole of his family, what is duty?
Based on the evidence presented in the article, it is concluded that in the premise of the rule of the most important and the important, it permits the permission and the need for homicide of duress.