D&C 128

As terrible as was the Prophet Joseph Smith's experience in Liberty Jail, I wonder that within these months of captivity, humility, and meditation, that the Prophet received the pure revelation or intelligence on his final work in this last dispensation. It seems that after this event, that the prophet's work seemed more focused on ordinances and work of salvation and of exaltation associated with the temple.

While in hiding, his letters now known as sections 127 and 128, seemed to reflect a great desire to communicate with the saints the importance of this last work. Not only baptism for the dead, but the Prophet says -

"And not only this, but those things which never have been revealed from the foundation of the world, but have been kept hid from the wise and prudent, shall be revealed unto babes and sucklings in this, the dispensation of the fulness of times." (Doctrine and Covenants | Section 128:18)

Because of the sacred nature of things, I'm sure the Prophet could not provide greater detail on the matter for -

"...It is sufficient to know, in this case, that the earth will be smitten with a curse unless there is a welding link of some kind or other between the fathers and the children..." (Doctrine and Covenants | Section 128:18)

Eventually these sacred thing were and our now revealed and administered in His holy temple. The Prophet made it clear of its purpose -

"...for it is necessary in the ushering in of the dispensation of the fulness of times, which dispensation is now beginning to usher in, that a whole and complete and perfect union, and welding together of dispensations, and keys, and powers, and glories should take place, and be revealed from the days of Adam even to the present time." (Doctrine and Covenants | Section 128:18)

This welding link in my mind is synoymous to being sealed.