Always keep your reader guessing.
Think of your story as a rousing game of hangman. Give your reader chances to guess letters, but don't reveal the entire word to them until the very end. Yeah, I hear ya . . . "Sheesh! Books are a collection of words. How the heck can you write a novel without revealing a word until the very end?! Are you crazy? On drugs? Been hit in the head with a ball-peen hammer?"
To which I respond with a resounding, "Uh, unbunch your undies there, Hoss. I'm talking allegory."
Webster says allegory means:
a story, poem, or picture that can be interpreted to reveal a hidden meaning,
typically a moral or political one.
And that's what you want to dish out one spoonful at a time to your reader so that by the end of your story they feel satisfied. Your writing needs to convey some kind of message, some takeaway value, without beating the reader's head to a bloody pulp with it. Let them figure it out. Don't be a big party pooper and go spoiling the surprise at the end.
Don't panic. You don't have to do this all in the first draft. This is something you can layer in later. Capture your story first. Often by the time you've penned the first sweeping saga, you'll discover exactly what your message is and will be able to go back and embellish.