I have grown up being taught that we can progress only if we make it to the Celestial Kingdom. As an adult I have heard other people say that we can progress from the Telestial Kingdom to the Terrestrial Kingdom and so on.
There is a vast difference between progression and “Eternal Progression”. “Eternal Progression” denotes God’s progression or way. The Lord told Enoch in Moses 7 of the Pearl of Great Price, that one of His names is “Eternal”. Those and only those who inherit the highest degree in the Celestial Kingdom will be blessed with “Eternal Progression” meaning there will be no limit or end to their progression.
The progression of all those who do not inherit the highest degree in the Celestial Kingdom will end as there are limits set to their progression. This doctrine was revealed to the Prophet Joseph Smith and recorded in the D&C 131:1-4
1 ” In the celestial glory there are three heavens or degrees;
2 And in order to obtain the highest, a man must enter into this order of the priesthood [meaning the new and everlasting covenant of marriage];
3 And if he does not, he cannot obtain it.
4 He may enter into the other, but that is the end of his kingdom; he cannot have an increase.”
Those who do not inherit the highest degree will not have the opportunity to become Gods, but rather they will become angels of God forever. This is recorded in the D&C 132:17
“For these angels did not abide my law; therefore, they cannot be enlarged, but remain separately and singly, without exaltation, in their saved condition, to all eternity; and from henceforth are not gods, but are angels of God forever and ever.”
Only those who enter into the new and everlasting covenant of marriage while in this life (meaning until one is resurrected) and are sealed by the Holy Spirit of Promise, will be worthy of this great blessing. This saving ordinance is performed vicariously in the Temple for those who did not have the opportunity while here upon the earth. In section 132:6 it states:
“Therefore, when they are out of the world they neither marry nor are given in marriage; but are appointed angels in heaven, which angels are ministering servants, to minister for those who are worthy of a far more, and an exceeding, and an eternal weight of glory.”
Only those baptized by one holding the Priesthood of God will be able to inherit any degree within the Celestial Kingdom. The baptismal ordinance also needs to be received during this life(as defined above). The progression of those who have not been baptized will be further limited as they will not be able to progress into the Celestial Kingdom.