When I was younger, I used to spend a fair bit of time looking at and refuting lots of alleged contradictions in the Bible. They were mostly really really easy, which gave me confidence that the people arguing against the Bible didn't really have any good arguments. Here's an example of one of the better ones.
Now I'm studying academic theology, it turns out that there's a different set of poor arguments for contradictions in the Bible (though there are a few overlaps, such as the Abiathar one). It's not that they are any better - they're just more difficult to see. One of them is the question of whether Paul saw Adam as being immortal or not before he sinned, and the resolution is kind of interesting.
If people want to argue that Paul saw Adam as immortal before he sinned, they tend to use Romans 5:12.
Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned
Romans 5:12, ESV
In context, that verse is clearly talking about Adam, and death entering into the world because he sinned. (In the context of Romans 5, it's obvious it's human death, which means that it's a poor argument for a Young Earth, but that's not really relevant here. The point is that Adam died because he sinned.
And if they want to argue that Paul thought Adam was necessarily mortal, they tend to use 1 Corinthians 15.
So is it with the resurrection of the dead. What is sown is perishable; what is raised is imperishable. It is sown in dishonor; it is raised in glory. It is sown in weakness; it is raised in power. It is sown a natural body; it is raised a spiritual body. If there is a natural body, there is also a spiritual body. Thus it is written, "The first man Adam became a living being"; the last Adam became a life-giving spirit. But it is not the spiritual that is first but the natural, and then the spiritual. The first man was from the earth, a man of dust; the second man is from heaven. As was the man of dust, so also are those who are of the dust, and as is the man of heaven, so also are those who are of heaven. Just as we have borne the image of the man of dust, we shall also bear the image of the man of heaven.
1 Corinthians 15:42-49, ESV
Paul's argument is a little involved, but his main point is contrasting Adam's body, which was "dusty" and perishable with Christ's resurrection body, which was "spiritual" and imperishable, the implication being that Adam was intrinsically mortal, even before he sinned.
So what do we make of it?
In Genesis, God says that Adam and Eve will die when they eat from the tree of the knowledge of good and evil. They eat the fruit, God judges them. But he doesn't kill them immediately, and his words to them don't have anything to do with death. Instead, after the "curse" in Genesis 3, we see this:
And the LORD God said, "The man has now become like one of us, knowing good and evil. He must not be allowed to reach out his hand and take also from the tree of life and eat, and live forever." So the LORD God banished him from the Garden of Eden to work the ground from which he had been taken. After he drove the man out, he placed on the east side of the Garden of Eden cherubim and a flaming sword flashing back and forth to guard the way to the tree of life.
Genesis 2:22-24, NIV
In other words, the death sentence on Adam is by stopping him from getting access to the tree of life. He never was intrinsically immortal, it was only because he had access to the tree of life. And that manages to neatly fit with what Paul says in Romans 5 and 1 Corinthians 15. Adam was mortal, but he had access to the tree of life, which would have enabled him to live forever. But when he sinned, he lost that access.
I was encouraged by seeing quite how neatly that works. Hope others are too.