Yishai, writing in the Shas newsletter, From Day to Day, said that if Israel makes "painful sacrifices" to reach an agreement with Palestinian Authority President Mahmoud Abbas, Hamas and other terrorist groups will resume violent attacks, the Jerusalem Post reported.
"We must stand up for our principles and never give up on them: Stop terror, recognize Israel as a Jewish state, stop provoking violence, and start negotiations without conditions. Certainly not the condition of a building freeze," he said.
Shas has opposed any freeze in construction in settlements on the West Bank since they were first imposed.
A Hamas militant shot and killed four residents of the Beit Hagai settlement near Hebron on Tuesday. The shootings were condemned by Palestinian Authority officials, while several Israeli leaders, including President Shimon Peres, said the country must continue negotiations with "those who denounce terror."