In Gethsemane, Jesus had a real choice: to go through with plan to redeem mankind which would mean suffering and agony to a degree that no one on earth can fully understand or abandon sinful, selfish, ungrateful mankind and return to the glory, joy and peace that he had known from eternity past.  Jesus chose to follow through with the plan because of the joy set before him.  The expectation of what was to come enabled him to endure the suffering in the short term.  What do we expect of God?