If you believe what is contained in the scriptures (the Bible) even though you may not understand everything, it still comes down to one simple point. Faith. I believe the WHOLE Bible, not just certain parts of it that I don't understand. I believe Noah's Ark existed because it's in the Bible. I believe people used to live to 900 or so years old because it's in the Bible. I believe God through Moses split the Red Sea because it's in the Bible. But to those who just think that The Bible is just a "book" and not the word of God, the scripture says that "this is foolishness to them." It comes down to you either believe it or you don't.
People say God doesn't exist because we can not see Him. The Bible says that if we were to ever look upon God "as He is" (in Spirit) our minds would not be able to handle it and we would go insane. Why, well... I believe it is because God is Holy and since we are not, "that which is imperfect (us) cannot look upon someone that IS perfect (God) and live. (just my opinion.) Can you see air? no...but it exists. Give me a scientific definition for what LOVE is? Explain to me why some of the most highly educated doctors of our day, when they have done all they know how to do in saving someones life and can do no more, when God heals them, they have no explanation because they can't "scientifically" explain it?
Sometimes God doesn't heal, sometimes babies die, when plane crashes occur, sometimes everyone on board is killed except one person...why did all those innocent people have to die on 9/11? And many other millions of questions of which we may never know an answer to. Whether we are willing to accept it or not, God does NOT have to account for Himself to anyone. He is God! Many people have tried to disprove the authenticity of the Bible through many years of scientific trials and tests and to this very day...no one has been ever been able to do it.
I believe the Bible is the word of God and every word in it is truth (even though I don't understand it all.) I believe that Jesus is God and He is the ONLY way to Heaven! If you don't believe that then that is up to you...God gave you that choice and that freedom. It's called free will. He has never nor will ever force himself on anyone. You can choose to believe whatever you want. But when Jesus said "I am the WAY, the TRUTH and The Life and no one will come unto the Father but by me" that is a very Bold statement. No other person or "deity" has ever made such a claim.
It all comes down to Faith of which God gave every person a measure of. Let's put it this way, I would hate to believe in something (or someone else) and find out I was wrong in the end. Are you really willing to "risk" where you will spend your eternity on that? I'm not. Whether you believe it or not....Hell is just as real as Heaven and they are both permanent. No person on this Earth will ever be able to understand everything about who God is or why He does what He does or doesn't do or...that He even exists. The Bible says He does...that all I need to hear.
If you are looking for God to prove and explain Himself so that you will believe, well there is scripture for that too. Jesus said..."blessed are those that believe, yet do not see." God simply wants us to trust Him and believe FIRST and then move on from there...but then again, He may not (or ever) explain himself. He is God and I am not, that is why I need Him. Some people in this world feel they don't need anyone including God. Well, that is their choice but i can guarantee you that if a person who believes that, ever find themselves in a situation that "even they" cannot handle", they might find themselves calling on the God of the Bible for help that THEY say doesn't exist.