What does Jesus demonstrate?

Christ demonstrated the fact of survival after death when after the death of the disciple Jesus, He showed Himself to many people in the form of that faithful worker, but it was not the poor, tortured and earthly body that His friends saw. 

The body they saw was a materialisation of that great soul used by the Master Christ for further teaching. 

Does it not seem strange that though they saw Him appearing and disappearing, they could yet imagine it was the flesh and blood body they had seen crucified?

―The Witness