Thank you for the question on understanding the Bible, “How would it be possible to understand the Bible if a person hasn’t been born again of the spirit?”
The Bible is a literature book. Anyone can read and understand the context of the Bible. One does not need the Spirit of God to know the facts of the Bible.
Agnostics, atheists, even other theists of other religions can explain or recount the biblical narratives. The issue is not understanding the biblical text, but it’s spiritual application to one’s life. Many people have heard or know about John 3:16, but few people believe John 3:16. They may even be able to recite it by heart, but they don’t believe that there is a God or that a God who loves them. They may not believe that Jesus is the Son of God, but a good moral teacher or a fictious person. He died as a martyr but not as the Savior of the world.
John 3 says this, “For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. 17 For God did not send his Son into the world to condemn the world, but to save the world through him. 18 Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son. 19 This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil. 20 Everyone who does evil hates the light, and will not come into the light for fear that their deeds will be exposed. 21 But whoever lives by the truth comes into the light, so that it may be seen plainly that what they have done has been done in the sight of God” (NIV).
I believe many people can explain the above verses, but who will believe it.
Summary: One can know the facts of the Bible and not believe the application of the statements to one’s life.
-Kingston