I got this off.
Aug 5, 1855 – Brigham Young tells apostles that after final judgment those consigned to terrestrial and telestial kingdoms will “eventually have the privilege of proving themselves worthy and advancing to a celestial kingdom but it would be a slow progress.”
It is kind of sad that the church seems to have stepped away from this teaching.
I suppose a slow progress in the eyes of eternity could be many hundreds, thousands, millions or billions of years.
Even if you had to wait Billions of years it is a more comforting feeling that one could eventually get the highest degree of glory.
They should bring this teaching back but just reiterate the slow progress part.