ESUS spoke of going away. There are 2 possibilities concerning what He was speaking about: His death or His ascension. I'm taking both. The thing He had said was that He was going away (John 16:6). We know that His death would bring a temporary intermission in His fellowship with His disciples. Then, His ascension would bring in a new dispensation; a new paradigm altogether. And both interruptions would conclude with a resurrection and reunion. His disciples did not understand this. They thought that the Messiah would live on the earth forever. So, if Jesus was the Messiah then they expected Him to continue as He was forever (John 12:34). His pending departure caused them to be confused and troubled.
It is the resurrection of Christ that transforms lamentation into rejoicing (John 16:20-24). It is the same resurrection power that gives us access to the Father (Romans 4:25, John 16:23 & 26). It is the power of God. And, God's power can produce love in the hearts of men who were once dead. The power of our living God is strong enough to affect faith in the hearts of men (who have had a predisposition toward doubt). God's power can make eternal spiritual truths perceivable to eyes that have been blind. God's power can take scattering cowards and turn them into a unit of gritty missionaries and willing martyrs. His power can give peace amid a storm. His power is out of this world.