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.

 6:28-29 They said to him: "What are we to do to work the works of God?" Jesus answered: "This is the work of God, to believe in him whom he has sent." 