Now they know that everything you have given me comes from you.
“Now” is probably temporal and means “now at long last”. Finally the disciples realize that everything Jesus has comes from God. This seems to indicate that the disciples finally realize that Jesus is divine. He is not just the Galilean Teacher nor even just the human Messiah; everything we see in Him is of God. When we look at Jesus our attention should not be on the man so much as on God. What really matters is that God became man for us.