When Jesus reigns on Earth, whatever the truth is—whatever things our theology was right about or wrong—all people will know God truly, without need for anyone to teach them. That’s one of the main reasons life will be, in so many words, “Heaven,” except that it will be Heaven on Earth, literally.
Even in the ages after Earth, everyone will understand the structures and systems of society. There won’t be political divides because both the needs and the ways to meet those needs will be widely know to everyone. When society is full of knowledge about God, that changes everything.
We’re not there yet, thankfully.
Even without sin, society must slowly learn about God. We can’t just have God come down, open the skies above everyone’s house, and download all truth. That would reduce us to minions. We must study and learn, ponder and work, in order to understand God.
Once all human society is filled with that knowledge about God, it won’t be from any download; it will be from our experience and from having seen Jesus face-to-face and having real fellowship with those who have done the same.
Learning comes from our own choice to do so, even in the next life. For all Eternity, we will never stop learning and God will never run out of things for us to learn about Him. So, in this sense, part of experiencing “Heaven on Earth” even now—of entering into Eternal Life even during this current, brief life—includes being students of theology—students of the knowledge of God. This begins with fearing only Him and nothing else, loving Him more than anyone or anything else, and pondering clear truths about love and self-sacrifice for others, from the smallest to the greatest circumstances of our daily lives.
Everything in your life—everything—was allowed or introduced by God as part of helping you learn about life, yourself, others, and—central to all knowledge—learning about Him. Look for His reflections—His fingerprints—in the world around you. Knowledge of God, after all, will abound in Eternal Heaven, but it is just as relevant and accessible here, in the world right around us.