Jacob’s daughter, Dinah is kidnapped and victimized by Shechem the son of Chamor. When her brothers hear about this and enter into negotiations with Chamor, they deceive him and trick him into having all the men in his city undergo circumcision. When the men were weak and recovering, Shimon and Levi, entered the city and waged war on the inhabitants, killing the men and capturing the women and children.
There is a lot of discussion in the commentaries about the justification or lack of justification for this action. Some maintain that the inhabitants of the city had transgressed the Noachide code which requires setting up a justice system; others maintain that it was an act of vengeance. The Maharal notes that the Torah obligates us to try to negotiate a peaceful settlement before going to war, and hence he is bothered by the fact that the sons of Jacob did not do so. He answers that we are only obligated to offer peace if we have not already been attacked, but if we are attacked, then as a sovereign nation we have to the right to respond. The family of Jacob, was already considered a nation, and the kidnapping and abuse of their sister by another nation was considered an act of war. Thus, Shimon and Levi were justified in waging war against the city of Shechem, as they were acting within their rights as a nation to defend itself against attacks.
