On the next day, the multitude that stood on the other side of the sea saw that there was no other boat there, except the one in which his disciples had embarked, and that Jesus hadn't entered with his disciples into the boat, but his disciples had gone away alone.

 His answer is extremely compressed and we must expand it and see what lies behind it. He said that God's work was to believe in him whom he had sent. Paul would have put it this way--the one work that God desires from man is faith. Now what does faith mean? It means being in such a relationship with God that we are his friends, not terrified of him any more but knowing him as our Father and our friend and giving him the trust and the obedience and the submission which naturally arise from this new relationship. How does believing in Jesus tie up with that? It is only because Jesus came to tell us that God is our Father and loves us and wants nothing more than to forgive, that the old distance and enmity are taken away and the new relationship with him made possible. 