I’ve always had some problems with the “God said it, I believe it, that settles it.” bumper stickers but I essentially agree that faith is the core issue.
Faith comes from hearing (and reading) the Word of God.
Once someone sees and understands the basic principles
written in the Word of God, like confessing Jesus Christ
as their Lord and believes God raised him from the dead,
we get born again. Romans 10:9,10. Then with that new
spiritual connection understanding of the Bible becomes
open and easier to grasp. This is why faith is the key.
Bible says- believe, then you see. The world says- let me
see then I’ll believe.