It really dives into deep theological truths. Namely, Jesus was separated from God - as in His life was completely separated from God. He had no power/authority to raise His life from the dead, God the Father had to give Him back that life when He raised Jesus from the dead.
That is not what Scripture says.
John 10:18 No one takes it from me, but I lay it down of my own accord. I have authority to lay it down, and I have authority to take it up again. This charge I have received from my Father." (ESV)
And we know that Jesus had the power to raise the dead.
So we cannot just dismiss the words said as something that was not meant to be taken seriously. In John 2 Jesus said He was going to lay down His life(which He did), and He was going to raise it up(which 'He' did not). However, we know that He will raise up His 'body' which is the church. God has given Him that charge to do. But it was The Father who raised Jesus - not Jesus Himself.
No one is just dismissing anything as not meant to be taken seriously. The point is that it is to go too far in making Jesus say something he does not to suggest that he was speaking of the Church. A plain reading of John 2 clearly shows us that Jesus was going to destroy his body and then raise it up. We cannot just go and say that Jesus meant something else entirely when John clearly states that Jesus was referring to his own body. There is no mention there of it referring to something else.
John 2:19 Jesus answered them, "Destroy this temple, and in three days I will raise it up."
20 The Jews then said, "It has taken forty-six years to build this temple, and will you raise it up in three days?"
21 But
he was speaking about the temple of his body.
22
When therefore he was raised from the dead, his disciples remembered that he had said this,
and they believed the Scripture and
the word that Jesus had spoken. (ESV)
Also, there is no mention anywhere else in the NT of the disciples remembering Jesus's words and then relating them to the Church. We have here something very clear and plain that needs no further explanation apart from the Trinity. Just because the Father is most often mentioned in raising Jesus doesn't mean that Jesus had no involvement and he must have meant something else. The Father raised him, the Holy Spirit raised him, and he raised himself. It is the work of the Trinity.
When you look at the parallel in John 10, we see Him again referring to this -
John 10:17
For this reason the Father loves me, because I lay down my life that I may take it up again.
He prefaced this statement with this -
"And I have other sheep that are not of this fold. I must bring them also, and they will listen to my voice. So there will be one flock, one shepherd."
So, in other words, He considers His 'life' that of a fulfillment of this "one flock".
That is not what Jesus is saying.
John 10:14 I am the good shepherd. I know my own and my own know me,
15 just as the Father knows me and I know the Father; and I lay down my life for the sheep.
16 And I have other sheep that are not of this fold. I must bring them also, and they will listen to my voice. So there will be one flock, one shepherd.
17 For this reason the Father loves me, because I lay down my life that I may take it up again.
18 No one takes it from me, but I lay it down of my own accord. I have authority to lay it down, and I have authority to take it up again. This charge I have received from my Father." (ESV)
Nowhere here is it stated or intimated that Jesus "considers His 'life' that of a fulfilment of this 'one flock'." The whole point is that there cannot be one flock
until he lays down his life and takes it up again. And that is what we see in Paul's writings:
Eph. 2:11 Therefore remember that at one time you Gentiles in the flesh, called "the uncircumcision" by what is called the circumcision, which is made in the flesh by hands--
12 remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world.
13 But now in Christ Jesus you who once were far off have been brought near by the blood of Christ.
14 For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility
15 by abolishing the law of commandments expressed in ordinances, that he might create in himself one new man in place of the two, so making peace,
16 and might reconcile us both to God in one body through the cross, thereby killing the hostility. (ESV)
And, as I have already shown, you are leaving out verse 18 where Jesus clearly states that he has the authority to take up his life again. He already had that authority before he died. And why shouldn't he? He is "the resurrection and the life" (John 11:25), he is the "Author of life" (Acts 3:15), and we see him raise the dead (John 11:43).