When one speaks of Israel and the idea of resurrection, it is to be remembered that the resurrection of the righteous dead, which went hand in hand with the establishment of the kingdom of God on earth (of which Jesus has already spoken), was a prominent hope of the people of Israel. There must be an awareness of the fact that the covenant people were not looking for an escape from this world, with an eye to joining their God in some type of far-off heavenly abode. They were looking for their creative, providential, covenant God to fulfill His promises to His people, establish His kingdom with and through and for them, and in so doing begin the long-expected restoration of His creation.
This is what Nicodemus, as a Pharisee, would have been thinking when Jesus spoke of eternal life, especially as Jesus did so in the context of the kingdom of God. Eternal life was not something that was to be enjoyed after one’s life was over, “over there,” but in the midst of the creation. The fact that Jesus puts an emphasis on His being lifted up, so that belief could be properly placed and that eternal life could be had, and doing this in connection with the Moses story, simply reinforces the long-treasured Jewish hope that was apparently shared by both Nicodemus and Jesus (probably along with the rest of Nicodemus’ compatriots).
Jesus has couched the entirety of the reported part of His conversation with Nicodemus in the history and hope of Israel. Naturally, this is the only way that it is possible to understand Jesus and His mission. He has broached the subject of eternal life with Nicodemus, with this eternal life being connected to a trust in, essentially, the covenant faithfulness (according to the promises) of Israel’s God. Having done this---set His words in the context of the long history of Israel, of Israel’s hope, and of the working of Israel’s covenant God, it would only makes sense that He is continuing to do that very thing when He goes on to say “For this is the way God loved the world: He gave His one and only Son, so that everyone who believes in Him will not perish but have eternal life” (John 3:16).
In essence, this is a repetition of what was said in the previous verse, with the addition of “will not perish.” It is very much akin to what happened in the story of Moses and the serpent. It is for that reason that it is impossible to separate out this verse so as to make it seem as if it is only a reference to Jesus Himself, independent of what comes before and after, and independent of the entire story of Israel. It is impossible to imagine that Nicodemus would have thought in this way (John 3:16 being isolated and standing on its own), and it is impossible to imagine that Jesus wanted Nicodemus to understand it in this way. It must, however, be a component of what Jesus wants to be understood, but if it is to be comprehended correctly, it must also fit well with the story that would have been playing out in the mind of Nicodemus as he converses with Jesus and hears these words.
Removing this popular and important verse from its surroundings (both in the text and its historical context) devalues its content, as it rips Jesus’ life and ministry away from the roots from which it grows, is nourished, and is almost entirely dependent if it is to have true meaning and efficacy. If this verse is removed from the historical context that has been provided, and seen only as Jesus saying that it is He that must be believed, so that eternal life (in the way that so many generally think of eternal life---going to heaven when upon death) can be had, then those that hear it or read it will miss out on the over-arching purpose and plan of salvation that the Creator God has for His world and His image-bearers. Just as certain “trigger words” have been used throughout the conversation---words that would have assuredly sparked certain thoughts and ideas in the mind of Nicodemus (as a Pharisee, member of the ruling council, and “teacher of Israel), Jesus’ use of “eternal life” (twice) is another one of those trigger words.