There is a fairly esoteric topic from LDS history called the law of adoption, which I find to be fascinating. I will leave the opportunity to you to look up that history in order to learn a little more about this practice, but my understanding and simple explanation is that as God had provided us with the ability to become sealed in families through the temple, the exact mechanism of the way this was done has changed throughout the years. Individuals used to be able to be sealed to differing leaders of the church who they were not related to in order to provide these valuable connections with each other.
Later on it was revealed that the way we should be doing sealings should be by us simply becoming sealed to our fathers, which will then eventually connect us all. Again this history is fascinating, but I bring it up quickly here to share the fact that most of what we have in modern Mormonism has evolved and developed. Even something as important as the mechanism that helps us to be able to be sealed to our families forever has developed through the years. Quentin L. Cook shared a thought in his talk that I feel relates to this idea. He said that “The essential doctrine of uniting families came forth line upon line and precept upon precept.”
We are a part of a church that believes in continuing revelation, which I believe is extremely exciting to ponder.