The Greek word "pisteuo" (believe/have faith/trust/commit) interpreted herein as commit is used by Jesus with a meaning of more than believing including trusting and acting on it.
6:30 They said therefore to Him:What sign do you do that we may see and commit to You? What do you do? 6:31 Our fathers ate manna from heaven in the desert, just as it has been written: 'He gave them bread from heaven to eat. 6:32 Jesus said therefore to them: "Amen, Amen, I say to you, Moses did not give you the bread from heaven, but My Father gives you the true bread from heaven; 6:33 For God's bread comes down from heaven and gives life to the order."
6:34 They said therefore to Him: “Lord, always give us this bread.”
6:35 Jesus said to them: "I am the life's bread; anyone, coming to me, wouldn't be hungry and anyone, committing to me, won't be thirsty ever. 6:36 But I say to you since you have seen and yet not committed. 6:37 Everyone whom the Father has given me, will have come to me and I would not cast out anyone coming to me. 6:38 Since I have come down from heaven not that I may do My desire but rather My sender's desire. 6:39 Now this is my sender's desire, that everyone, who remains given to me, I may not destroy out of His, but I will raise up him on the last day. 6:40 this then is my Father's desire, that everyone, who sees the Son and commits to Him, have eternal life, and I will raise up him on the last day."
(6:34) The messiah was to reinstitute the manna and the Jews hoped it would be forever.
(6:36) Jesus knows they only want to use Him and haven't committed themselves. They believe but don't trust themselves to Him.
(6:39) He will only raise up those who remain given to him.
(6:40) He will only raise up those who both physically see Him and commit to Him – the Greek verb "theoreo" refers to viewing or seeing or consulting, having a physical image, not merely knowing
6:41The Jews were grumbling therefore about Him since He said: “I am the bread which came down from heaven” 6:42 and they said: “Is not this Jesus, Joseph's son, whose father and mother we know? How does he now say that “I've come down from heaven”? 6:43 Jesus replied and said to them: Do not grumble among yourselves” 6:44 No one is able to come to Me if the Father, My Sender, doesn't draw him and I will raise up him on the last day. 6:45 It is written in the Prophets: 'and all will be divinely taught', all who heard from the Father and learned, all come to me, 6:46 Since no such has seen the Father, except Him, the one coming from God, He has seen the Father. 6:47 Amen, Amen, I say to you, the committing one has life eternal. 6:48 I am the life's bread 6:49 Your fathers ate the manna in the desert and died. 6:50 This is the bread which comes down from heaven, that one would eat of the same and not die. 6;51 I am the living bread which came down from heaven: if anyone were to have eaten this bread, he will live to eternity, yet however, the bread which I will give is My flesh for the order's life.
6:52 The Jews therefore quarreled with each other saying “How can he give us His flesh to eat?”
The Jews note that he is going to give His flesh to eat and yet instead of correcting this as the uncommitted heretics believe he states that you must eat His flesh. Thus in some way He must be able to produce His flesh for us to eat.
6;53 Jesus said therefore to them: "Amen, Amen, I say to you, if you would not eat the flesh of the Son of Man and drink of the same's blood, you will not have life by Him 6:54 Anyone feasting on My flesh and drinking my blood has eternal life, and I will raise up him on the last day. 6:55 for My Flesh truly is food and My Blood truly is drink 6:56 anyone feasting on My flesh and drinking My Blood remains with Me and I with him 6:57 Just as the living Father sent me, and I live because of the Father, anyone feasting on Me, will live because of Me. 6:58 This is the bread which came down from heaven, Not as the fathers ate and died, anyone eating this bread will live into eternity."
6:59 He said this in the synagogue as he was teaching in Capernaum. 6:60 Many, therefore, having heard from the disciples themselves said “This message is hard, who can obey it?” 6:61 But Jesus knew by Himself that the disciples were grumbling about this themselves. He said to them: "This scandalizes you? 6:62 What if you would see the Son of man rise up where He was before? 6:63 The Spirit is who makes alive, the flesh doesn't benefit anyone. The matters which I have spoken to you are both spirit and life. 6:64 But there are some of you who aren't committing. " For from the beginning Jesus knew who are the uncommitted ones, and who is the one betraying him.
(6:62) Jesus body would then be capable of doing the miraculous.
(6:63) Jesus is potentially teaching two things in this verse thus both we must assert as true:
(1) It is the Holy Spirit who is responsible for giving us eternal life, not our sinful human nature
(2) It is the Divine Spirt in Jesus' flesh that gives life not merely the His human flesh
Further the matter of eating His flesh is life-giving and a way of life.
6:65 and He was saying "Because of this I have said to you that no one can come to me except who has been given by the Father." 6:66 Out of this, many of the same disciples went back, for they were even no longer walking with Him.
The disciples understand he wants them to eat His flesh and they know He means that it will not be done in some metaphorical way. Jesus could have corrected them so they would remain, but He doesn't, thus He must mean we must eat His flesh and drink His blood in a real way.
6:67 Jesus said therefore to the twelve: “Yet you don't want to go away?” 6:68 Simon the Rock answered Him: “Lord, to where will we depart? You possess eternal life's matters. 6:69 And we have committed and recognized that you are God's Holy One.” 6:70 Jesus answered them: "Did I not choose you twelve? Yet out of you, one is a devil."
Jesus knows that Simon Peter and the rest aren't quite fully committed yet but most of them desire to commit fully, however, Judas will not.
6:71 He was speaking this now about Simon Iscariot's Judas: for he as one of the twelve was about to betray Him.