Jesus answered them, "Destroy this temple, and in three days I will raise it up."
The Jews thought that Jesus was offering to rebuild Herod’s temple within three days if they would knock it down. His ability to do so would have been a miraculous enough sign for any of them. Furthermore it would have demonstrated His authority to regulate temple service. However they were unwilling to fulfill their part of the sign. By suggesting this action Jesus was also implying that the old temple and its service had served its purpose. He had come to establish a new temple and a new way of worship.