Genesis 34:24-25

24All the men who were at the city gate agreed with Hamor and Shechem. So every male in the city was circumcised.

25Three days after the men were circumcised, they still had a lot of pain. Then two of Jacob's sons attacked Shechem's men with their swords. None of the men were ready to fight. Jacob's two sons were Simeon and Levi, Dinah's brothers. They killed every male in the city.