I suggest that you reread John 6. Jesus answers their concerns about what He said. He repeats that only God can save and choose. This is a huge contention today. People cannot accept that it is God who does the choosing, not man. They think that this makes God unjust. Read the whole chapter again without prejudice. The people that left Jesus He already determined to be unbelievers who would not believe. They followed Him because they thought they could get fed food for nothing.
John 6:26 Jesus answered them and said, Verily, verily, I say unto you, Ye seek me, not because ye saw the miracles, but because ye did eat of the loaves, and were filled.
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
John 6:36 But I said unto you, That ye also have seen me, and believe not.
Jesus plainly taught that it was by coming to Him and believing that one was saved. It wasn’t by anything else at all.
40 And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.
John47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
Again I ask you by the mercies of God to reread John 6 without prejudice.
Au contraire! You can’t accept the gifts that God bestows! Even on the lost.
I ask you to re-read John 6 without prejudice. Jesus plainly teaches that he intends to give us his flesh as food, and his blood as drink.
He was perfectly capable of telling us to have faith, to believe, to have trust, etc., without talking about munching and chewing on his flesh, and drinking his blood.
He was capable of telling us that he intended to give us eternal life, without telling us that we must eat his flesh and drink his blood in order to have eternal life.