Dear Dave,
There are some thing we will not know until our knowledge has been made full and complete in Christ at our final transformation. This is one of those questions that really has no definitive answer in scripture. Would Adam have lived forever in the flesh if He did not sin? Only God knows.
I believe God's intention from the beginning is that we were to be united as one with God. Our life comes from being united with Him. Our death comes from being seperated from Him.
I would like to make a comment on a few other things this person said however.
Firstly, the writer calls this a test. How impersonal is a test? If your parents tried to test your love, wouldn't you be offended? This was not a test. God was honoring Adam and Eve by giving them a choice. He gave them free will, and then gave them the right to choose. God could have easily removed the tree of Knowledge from the garden so that they could never sin. Instead, God gave them a choice. God knew what they would choose. However, He gave them the choice in order to honor them and love them.
In the story of the prodigal son told by Jesus, the father did the same thing. The son asked for his inheritance and took off. The father gave it to him. The father let the son have his choice. The father could have stopped the son. Instead, he let the son go.
Secondly, is death really a punishment?
The second death is a punishment. The first death was a consequence. God gave Adam and Eve a choice that had consquences. If you eat off the tree, then you will surely die. He was trying to tell them, "If you eat off the tree, then you will be seperated from me. And without me, you will die." When they ate from the tree, God then went looking for Adam. Why? Did not God see Adam? This is because Adam had changed. Did God change Adam? No. Adam changed due to sin. God no longer recognized Adam. Instead, Adam had become something entirely different.
Death was not a punishment. It is a consequence. Paul described it as a wage in Romans 6. We earned death. A punishment is something we deserve.
Think of this parable.
John 9:1-3
1 As He passed by, He saw a man blind from birth. 2 And His disciples asked Him, "Rabbi, who sinned, this man or his parents, that he would be born blind?" 3 Jesus answered, "It was neither that this man sinned, nor his parents; but it was so that the works of God might be displayed in him.
The disciples were focused on this idea of the a person getting what they deserve. They were trying to figure out, "Why did this man deserve this?" Jesus quickly points out that it had nothing to do with deserving. Rather, it is was done so that God could give in love. It was done so God could be glorified.
Death is a consequence. And because of it, God may be glorified through it. God can work in us to save us. He can give us life. God does not want anyone to die.(Ezekiel 18:32) From the beginning, death was our own choice. We chose death. We chose to seperate ourselves from God. When Satan tempted Eve, he said, "You will be like God." This was Satan's way of saying, "You will be free. You won't have to obey Him. You can do things your own way, how you want to do it. You can be your own God."
The sin of Adam and Eve was to trust in things other than God. God told them, "If you eat of the tree, you will surely die." He didn't say, "If you eat of this tree, I will kill you." God was warning them. Did they trust in God? Did they heed His warning?
Their faith failed them. They didn't believe in God. Instead, Eve gave into the temptation. She trusted herself more than God. And Adam trusted in Eve more than God. Adam was standing right there when it happened, and he still took the fruit from Eve.
They put themselves first, without putting God first. And so, they sinned. From the beginning, our sin has been a problem of love. We were created to love God. We have failed. We have failed miserably. The number one commandment is to love God with all your heart, mind, body, and soul. Adam and Eve did not love God. If they did, they would have trusted God. They would have had faith in God. Eve would have told the Devil, "Flee Satan, for God said I would surely die."
Hope this helps,
In love,
Blake