You are still avoiding an explanation of Jn 6:29. That's my last word on the matter.
I'm not avoiding it. I'm sorry you feel that way. I think that you expect me to say something you want to hear, and anything else constitutes avoidance?
John 6
22 On the next day the crowd that remained on the other side of the sea saw that there had been only one boat there, and that Jesus had not entered the boat with his disciples, but that his disciples had gone away alone.
23 Other boats from Tiberias came near the place where they had eaten the bread after the Lord had given thanks.
24 So when the crowd saw that Jesus was not there, nor his disciples, they themselves got into the boats and went to Capernaum, seeking Jesus.
25 When they found him on the other side of the sea, they said to him, "Rabbi, when did you come here?"
26 Jesus answered them, "Truly, truly, I say to you, you are seeking me, not because you saw signs, but because you ate your fill of the loaves.
27 Do not labor for the food that perishes, but for the food that endures to eternal life, which the Son of Man will give to you. For on him God the Father has set his seal."
28 Then they said to him, "What must we do, to be doing the works of God?"
29 Jesus answered them, "This is the work of God, that you believe in him whom he has sent."
30 So they said to him, "Then what sign do you do, that we may see and believe you? What work do you perform?
31 Our fathers ate the manna in the wilderness; as it is written, 'He gave them bread from heaven to eat.'"
32 Jesus then said to them, "Truly, truly, I say to you, it was not Moses who gave you the bread from heaven, but my Father gives you the true bread from heaven.
33 For the bread of God is he who comes down from heaven and gives life to the world."
34 They said to him, "Sir, give us this bread always."
Verse 29 comes as a response to a question Jesus was asked. A person in the crowd that followed Him, asked Him what they could do to be doing the works of God. This question was in response to them hearing Jesus telling them not to labour for the food that perishes, but that which leads to eternal life - which comes from the Son, who the Father has set His seal.
So they obviously wanted to know how to "work" for this food that leads to eternal life. They knew, as all men did back then, that you worked for your food. They were not like people these days that just go get some food from the store. Jesus told them they should labour for the better food.
Not wanting them to think they could actually acquire it through their works, He told them the "work" of God, that is, the work that God wants them to do, is to believe in the Son.
So they understood it very clearly that the labour, which is the work they needed to do, was to believe. Just as they knew they could not just go to the fields and get their food to eat for the body, they understood that belief was not just a one time "thought" they were to have in the Son. This is why they asked Him for a sign. They wanted absolute assurance they were not going to be "working" for something that was not true.
This is the same principle we find Paul telling Timothy.
2 Timothy 2
1 You then, my child, be strengthened by the grace that is in Christ Jesus,
2 and what you have heard from me in the presence of many witnesses entrust to faithful men who will be able to teach others also.
3 Share in suffering as a good soldier of Christ Jesus.
4 No soldier gets entangled in civilian pursuits, since his aim is to please the one who enlisted him.
5 An athlete is not crowned unless he competes according to the rules.
6 It is the hard-working farmer who ought to have the first share of the crops.
7 Think over what I say, for the Lord will give you understanding in everything.
You see, you cannot just believe for a moment and then go on to do other things. Just as it is not right for a farmer to go out in the field, spend an hour out there working, and then expect to come back at harvest time and receive a share. It is the hardworking farmer who should be the one to have first share in the crops.
The whole point of John 6:29 is to tell the people that they cannot do anything to earn eternal life, but rather they should labor in the faith of Him to receive it from God. There is zero implication given that what they needed to do was just believe once and go on their way - expecting that a moment in time belief would produce the food that leads to eternal life.
I still think the fact that some don't understand that eternal life is Jesus, is what throws people's understanding of it off. We receive eternal life(Christ) when we believe, through the Spirit coming to dwell in us. If we abandon that faith(belief) then just like a farmer should not expect crops if he abandons a field, we should not expect eternal life to continue in us.
This is why Romans 11:20-23 is applicable. Also we see it spoken of in Colossians.
Colossians 1
15 He is the image of the invisible God, the firstborn of all creation.
16 For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities-all things were created through him and for him.
17 And he is before all things, and in him all things hold together.
18 And he is the head of the body, the church. He is the beginning, the firstborn from the dead, that in everything he might be preeminent.
19 For in him all the fullness of God was pleased to dwell,
20 and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.
21 And you, who once were alienated and hostile in mind, doing evil deeds,
22
he has now reconciled in his body of flesh by his death, in order to present you holy and blameless and above reproach before him,
23
if indeed you continue in the faith, stable and steadfast, not shifting from the hope of the gospel that you heard, which has been proclaimed in all creation under heaven, and of which I, Paul, became a minister.