The question of advancement within the great divisions of glory celestial, terrestrial, and telestial; as also the question of advancement from one sphere of glory to another remains to be considered. In the revelation from which we have summarized what has been written here, in respect to the different degrees of glory, it is said that those of the terrestrial glory will be ministered unto by those of the celestial; and those of the telestial will be ministered unto by those of the terrestrial” that is, those of the higher glory minister to those of a lesser glory. I can conceive of no reason for all this administration of the higher to the lower, unless it be for the purpose of advancing our Father’s children along the lines of eternal progression. Whether or not in the great future, full of so many possibilities now hidden from us, they of the lesser glories after education and advancement within those spheres may at last emerge from them and make their way to the higher degrees of glory until at last they attain to the highest, is not revealed in the revelations of God, and any statement made on the subject must partake more or less of the nature of conjecture. But if it be granted that such a thing is possible, they who at the first entered into the celestial glory”having before them the privilege also of eternal progress”have been moving onward, so that the relative distance between them and those who have fought their way up from the lesser glories may be as great when the latter have come into the degrees of celestial glory in which the righteous at first stood, as it was at the commencement. Thus: Those whose faith and works are such only as to enable them to inherit a telestial glory, may arrive at last where those whose works in this life were such as to enable them to entrance into the celestial kingdom... they may arrive where these were, but never where they are.”

B. H. Roberts, New Witnesses for God 1:391-392.