Jesus therefore said to them, "Most assuredly, I tell you, it wasn't Moses who gave you the bread out of heaven, but my Father gives you the true bread out of heaven.

 Jesus was well aware that some would not only reject his offer but would reject it with hostility. No man can accept him unless he is moved by the Spirit of God to do so but to the end of the day a man can resist that Spirit. Such a man is shut out not by God, but by himself. 