The best way a person can make a clear literal point is
repetition of the same
message in different ways. Jesus
did this. Those around him
clearly understood what he was saying--cannibalism and the drinking of blood--both forbidden by Mosaic Law.
John 6:60,66
Then many of his disciples who were listening said,
"This saying is hard; who can accept it?" ...
As a result
of this, many (of) his disciples returned to their former
way of life and no longer accompanied him.
Had these disciples mistaken the
meaning of Jesus' words, Jesus
would surely have known and
corrected them. He didn't. They had clearly understood his
meaning--Jesus' flesh was to be really eaten; his blood to be really
drunk.