We authors love this.
There isn't much I understand about the creation of a universe, but the creation of a novel I understand.
There are behind the scenes efforts that the author undertakes to give a character depth. It would seem that I, as the writer, call all the shots. This isn't always true.
I certainly have an end in mind, points along the path that my characters must reach, and a story to tell. However, the journey is often full of surprises.
The characters do things I don't expect. They complicate things. They say things they shouldn't, feel things I didn't plan for and sometimes take detours. It's my job to let them get there. To give them room to grow while guiding them back into place.
Sounds like free will, right?
I can relate to God in this. How we stray from His plan and seem to almost entirely change the story, to be led back into place by a gentle heavenly nudge (or sometimes a righteous smack upside the head).
There are things that will happen to us in our journey toward heaven, growing lessons that happen outside of the written book. They are private messages from God. Moments that shape our character and define us.
The world doesn't know everything that happened to make us stronger and they don't need to.
My characters have this private learning time too. I actually write diaries of their private thoughts and prayers. I write about their dreams, their fears. I use this writing as research to build stronger characters.
This is all information the reader won't have, but it makes the characters alive. Hopefully, it's what will give them the power to effect you.