What is the point of the Garden of Eden story?
Many Christians believe the point of the story is to explain how humanity fell into sin. While there may something to that, it must be always kept in mind that NONE of the New Testament evangelism even mentions the fall of Adam. If the Garden of Eden is a key part to the story of Christina salvation, you would never know it from reading the Gospels and the many evangelistic sermons in the book of Acts.
In fact, I claim the text makes clear in flashing neon lights what the story is about, and we only fail to see it because we have been taught to read Protestant theology into the story.
It is true that the Garden of Eden story is linked to man's mortality (which is different from his damnation), but not in the way people often are taught. Even after sinning, humanity could have had immortality had Adam eaten from the tree of the fruit of life. [Genesis 3:22] and the principal reason God kicks Adam out of the Garden is that (for whatever reason) God did not want Adam to both know the difference between good and evil and be immortal.
But the story answers other questions as well. For example, it explains why snakes have no legs [Genesis 3:14], more importantly it explains where our conscience, our ability to determine right and wrong, comes from [Genesis 3:5-7, and Genesis 3:22 again].
Most importantly, it acts as a key lead-in to Noah's story!!
Yes, I believe it is not an over-estimation to say that the single most important theme of the Garden of Eden is that it acts as a prequel to Noah's work. It does not appear that way to us because we focus on the least important aspect of Noah and miss a key point to the Garden of Eden story.
When you think of Noah, you think of the flood. And when you think of the flood story, the conclusion everyone remembers is the rainbow as a proof that God will not destroy the Earth by flood. To us Americans living in the land of plenty, where true poverty and hunger are extremely rare, the dramatic story of the flood and the destruction it wrought on the Earth is the key point. But to the Israelites/Hebrews reading the story of Noah, the flood is not the real point.
When we look at the passage where God makes a covenant with Noah [8:21-22] we note two blessings given to Noah. The one everyone knows (the rainbow, etc.), and another one "I will never again curse the ground because of humankind, for the intention of his heart is evil from his youth."
Recall that in Genesis 3:17-19 the ground is cursed because of Adam's sin. Prior to this curse Adam was still expected to work in the garden and tend it [Genesis 2:15]. The curse made the work much harder. Indeed, Noah gets his name because he was appointed to reverse this curse: Genesis 5:29 reads “Out of the ground that the Lord has cursed this one shall bring us relief from our work and from the toil of our hands.” [The Hebrew word Noah sounds like the word for "bring us relief" and there are several puns made on this in the ensuing story of the flood.]
This reference to agriculture is also found in Noah being the first person to plant a vineyard.
In fact, Noah more than reverses the curse because not only does God remove the curse on the ground, but for the first time God allows humanity to eat animals rather than only plants. [Genesis 9:3] This is another reason why the curse on the ground was so onerous: humanity depended completely on agriculture rather than ranching.
So I think the most significant part of the Garden of Eden, at least for the original readers, was its role in the general drama of sustenance. Before the garden, no plants were cultivated because it had not rained and there was no one to tend them. Adam is made and put in the garden to tend the plants there. Adam's sin causes the ground to be cursed, making life hard. Noah gets his namesake from the hope that he will break the curse, and sure enough that is what happens. He more than breaks the curse because the ground is no longer cursed and humanity can now eat animals as well.
How very different we read the story.