The resurrection was necessary to show that Jesus really was more than just a religious prophet. It is the basis of the entire Christianity! So, I think he had to die not mainly for the sins but to later resurrect himself as the son of God. Of course, it would have been much more spectacular to actually resurrect himself on the very cross, smash the crosses to pieces and walk away triumphantly. It would have been a miracle none would have been able to deny... 


