Don't work for the food which perishes, but for the food which remains to eternal life, which the Son of Man will give to you. For God the Father has sealed him."

 It is little wonder that the disciples found the discourse of Jesus hard. The Greek word is skleros ( G4642) , which means not hard to understand; but hard to accept. The disciples knew quite well that Jesus had been claiming to be the very life of God come down from heaven, and that no one could live this life or face eternity without submitting to him. 