How do the traditions of Peace and truce of God tie in with call of a Crusade?

The traditions of Peace and Truce of God aimed to limit violence within Christian communities and societies. The call for a Crusade, on the other hand, involved the authorization of military campaigns against external enemies such as the Muslims in the Holy Land. While both concepts involved Christian concepts of peace and justice, the Crusades often operated outside the constraints of the Peace and Truce of God movements.