What is it that convinces us anything is real or true? Proof, objective proof. It's how we know we can trust a product, person, or perspective.
But what about the Bible? While many treat it like a scientific book that can be proven through processes and argument, it is, in fact, not objectively true. Yes, there are large portions that are historically provable, but the teachings of our Holy Book are not.
There is no proving the deepest realities of the Christian faith. There is no objective proof or scientific explanation for the Trinity, the hypostatic union, the virgin birth, the resurrection of Jesus, the ascension, creation of the universe ex nihilo, forgiveness, grace, heaven, or hell. We believe these to be true and can prove not a bit of it.
That is perfectly OK, and we should be OK with it even as it sometimes makes us squirm. It's OK because the message of the Bible is true in other, better ways.
The Bible is persuasively true. Objective proofs explain the pieces of the physical world in such a way that cause and effect and scientific reality become clear. But there are no objective proofs for those realities that aren't composed of objectives. Objectivity is limited to the physical. Beyond that, any attempt at it is a misguided waste of energy. Persuasion, though, is what expands the mind beyond the realms of the physical. It pushes the imagination and intellect to explore and embrace those things that, while they can't be seen or completely explained, are compelling and completing to life. So the Bible is true because it persuades.
It persuades because it is supernaturally true. It is in the realm of the supernatural that objectivity falls all to bits because it is simply inadequate for the task. Where objectivity proves that 1+1+1=3, the supernatural tells us that 1+1+1=1. And they are both right. The Bible is true in ways far beyond proof, but never less than proof. Objective proof is not the highest truth. If anything it's the lowest common denominator of truth because it's merely math and science. The supernatural is what opens the hearts and minds of humanity to persuasion. It is what captures the soul in that inescapable grasp of belief. The supernatural truths of the Bible are what we know by faith. They are true and thus we know them, but they are not true because we do.
All of this is precisely why so many have doubts and find Christianity difficult to believe. So we must respond as those who hold to persuasive, supernatural truth and not merely objective proof. Ours is not primarily to argue and debate, but to open the Book and let the supernatural do the persuading. Ours is not to have all the answers in an ordered fashion, but to remember that having all the answers is not what saves. It is the miraculous work of the supernatural to persuade hearts into believing that saves.