We believe we will achieve immortality early in the 22nd century. Once the last person dies, the world will begin the work of resurrecting their parents, and making things 'just'. As all the parents did all the work, and gave an immortal heavenly world to their children, so until everyone that did all the work is also resurrected, things will remain unjust. This work will continue till the last human has been resurrected. The time between these two events (when the last person dies, and the last person is resurrected) is referred to by some religions as "The Millennium".
Religions that believe in Disembodied spirits, or Ghosts, predict the first thing we will experience after we die will be our dead friends and family, and maybe God, separated from the living. We, instead, predict the first thing we will experience will be our surviving children, having become Gods, resurrecting us into a world where nobody will ever need to be separated, ever again.
This scenario has been described in a fan fiction short story based on the Characters from Cameron's movie Titanic by Brent Allsop called "1229 Years After Titanic"