Genesis 34:14
And they said unto them, We cannot do this thing, to give our sister to one that is uncircumcised; for that were a reproach unto us: And they said unto them, We cannot do this thing, to give our sister to one that is uncircumcised; for that were a reproach unto us:
The words were the reply of Dinah's brothers in the history of her going out to visit the daughters of the land and of the violence that followed at Shechem. The brothers named in that violence were Simeon and Levi. Dinah's venturing out into association with the ungodly brought sorrow.
The stated refusal to give their sister to an uncircumcised man was used as a deception against the Shechemites. The revenge that the brothers then carried out, though provoked, was a grievous sin. It was a cruel, revengeful destruction of the people of Shechem.