Genesis 34:22
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. 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.
The condition laid down was that every male among Hamor and Shechem's men submit to circumcision as the price of dwelling together with Jacob's household and becoming one united people. That proposal was put forward by Simeon and Levi not honestly but deceptively, as cover for a concealed plan of revenge. Jacob himself was kept ignorant of their intent while they plotted against the Shechemites. When the agreement had been secured, they turned it into an opportunity for violence and bloodshed, cruelly destroying the Shechemites.