Jesus said on his last night before his crucifixion,
I came forth from the Father, and am come into the world: again, I leave the world, and go to the Father (John 16:28).
I agree with what Gary Burge says about this declaration by the Lord Jesus Christ:
This is the essence of the Christian faith, distilled in its most essential form.
Yet Joseph Smith rejected this incarnational paradox. He wanted in on the action by suggesting that he, too, literally came from the Father. He would tell you that this is one of the biggest things that those early disciples didn’t understand as they sat puzzled over Jesus’ farewell discourse – that they were not grasping that they all came from the Father and heaven’s abode just like Jesus. The vision of Joseph Smith was to empower every human to literally claim this path for themselves: (1) I preexisted with my Father, (2) I came from heaven to this earth, (3) I am leaving, and (4) I will return to my Father again. This is the distilled essence of Joseph Smith’s “Christianity” – that we all have a literal right to John 16:28.
But historic Christianity makes the fundamental assertion that no other human can literally claim what Jesus asserted in John 16:28. That truth has never needed a restoration. It is clear in every age. It has been a black and white theological proposition through the 2000 years of history for the saints of the Church of Jesus Christ who submit to what the Savior says exclusively about himself in John’s Gospel.