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“By the time Christ comes we are expected to have done all that is within our power to do now for our dead. That does not mean we are going to do all that is to be done, because it will go on during the millennium. The great work of the millennium will be the salvation of the dead, and those who are on the other side will help us, too, by bringing us information. The ordinances for the salvation of the dead are mortal ordinances, because all these ordinances pertain to this life, and immortal beings cannot perform them.
“Those who will be living here then will be in daily communication with those who have passed through the resurrection, and they will come with this information, this knowledge that we do not have and will give it to those who are in mortality saying. 'Now go into the temples and do this work; when you get this done, we will bring you other names.’ And in that way every soul who is entitled to a place in the celestial kingdom of God will be ferreted out, and not one soul shall be overlooked.”
– Joseph Fielding Smith, compiled by Bruce R. McConkie,
Doctrines of Salvation, Vol 2, pp 166-167, Bookcraft, 1955.