Throughout our lives messages of truth and wisdom are thrown at us, but most of these bounce off. We'll see, hear and even feel the message, but we don't absorb it and it falls away.
Years later, when we have grown into a different frame of mind, that message will again hurl itself in our direction - but this time it hits our brain like a bolt of lightning - and we have a massive dawning realization.
Then we say to ourselves "I heard this message before, why didn't I understand its significance?"
This happened to me - literally 5 minutes ago. I watched a movie that had a lot of gnostic inspiriation in it about ten years ago. In fact, it seems the entire plot is based on gnostic principles. While I was very intrigued by the movie I was disappointed in the ending and felt like it fell kind of flat. It wasn't until today that I understood the full meaning of what I had seen, presumably because until now I wasn't ready to hear the message. Now it makes perfect sense to me, and I want to watch it again and see if there is any nuance that I had missed before.
Humans are linked to each other and to the entire universe, but because of our nature we cannot see 99.999% of that link. We essentially walk around blinded to the truth and unable to access most of what is out there. When we do access it, it is often in the form of the stories that we tell - but we often view these stories as unique creations of our minds and fail to recognize the constant flow of truth behind them. This doesn't mean that every story told by man is 100% true, it means that every story has some truth in it. Whether or not this truth makes it's way to our concious minds depends on where we are in our spiritual development.
We are bombarded with messages every single day, which contain truths about ourselves and the universe, but most of them bounce off of us like darts thrown at a rubber ball. It takes anywhere from one to a thousand attempts for that dart to pierce the ball and expose what is inside to everything that is outside.
We cannot force ourselves (or anyone else) to open up to these messages, this is something that must come from within when the person is ready. All we can do is try to be open to the possibilities, and give the message a little bit more chance to drive itself home and enlighten us just a bit more.