Yeshua quoted Moses
Deut 8:3 And he humbled thee, and suffered thee to hunger , and fed thee with manna, which thou knewest not, neither did thy fathers know ;
that he might make thee know that man doth not live by bread only, but by every word that proceedeth out of the mouth of the L-RD doth man live .
by saying: It is written , Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.
This is 'the word', and in John we read that 'the word became flesh'. This is what we are to eat of him, not a lamb or bread.
Secondly in John Yeshua says something that confuses the Jews who heard it. Remember the Torah teaches not to drink blood and not to eat humankind. This ties into what Moses was saying in Deut. about being fed from heaven.
44 No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day. 45 It is written in the prophets, And they shall be all taught of God. Every man therefore that hath heard , and hath learned of the Father, cometh unto me. 46 Not that any man hath seen the Father, save he which is * of God, he hath seen the Father. 47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
48 I am that bread of life. 49 Your fathers did eat manna in the wilderness, and are dead . 50 This is the bread which cometh down from heaven, that a man may eat thereof *, and not die . 51 I am the living bread which came down from heaven: if any man eat of this bread, he shall live for ever: and the bread that I will give is my flesh, which I will give for the life of the world.
52 The Jews therefore strove among themselves, saying , How can this man give us his flesh to eat ? 53 Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you. 54 Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day. 55 For my flesh is meat indeed, and my blood is drink indeed.
56 He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him. 57 As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me. 58 This is that bread which came down from heaven: not as your fathers did eat manna, and are dead : he that eateth of this bread shall live for ever.
And the Word was made flesh...............
59 These things said he in the synagogue, as he taught in Capernaum. 60 Many therefore of his disciples, when they had heard this, said , This is an hard saying; who can hear it? 61 When Jesus knew in himself that his disciples murmured at it, he said unto them, Doth this offend you? 62 What and if ye shall see the Son of man ascend up where he was before? 63 It is the spirit that quickeneth ; the flesh * profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
It is his words that bring life. He was speaking a 'hard saying' because it sounded to them like he wanted them to eat his body and drink his blood as the heathens did to their gods. This they knew was forbidden so they didn't understand.
But what I believe he was saying was that he was the word and the word made flesh to be able for us to hear the word and not be afraid as that day at the mountain. But that word should be in us, that is how we become one with him and one with G-d. He is speaking of everlasting life, matza and wine do not extend you life one day, not one minute.
We are not to eat any blood, of any creature, for that is the life.
Everlasting life comes from 'eating and drinking' of the word of G-d, not eating human flesh, or a lamb, or unleavened bread or wine. it is the word that brings everlasting life, and this is the bread that came down from heaven.