Genesis 34:23

These men are peaceable with us; therefore let them dwell in the land, and trade therein; for the land, behold, it is large enough for them; let us take their daughters to us for wives, and let us give them our daughters.

Only herein will the men consent unto us for to dwell with us, to be one people, if every male among us be circumcised, as they are circumcised.

And unto Hamor and unto Shechem his son hearkened all that went out of the gate of his city; and every male was circumcised, all that went out of the gate of his city.

And it came to pass on the third day, when they were sore, that two of the sons of Jacob, Simeon and Levi, Dinah’s brethren, took each man his sword, and came upon the city boldly, and slew all the males.