D&C 110

I had a thought this morning that may not necessarily be established doctrine, but the Lord has stated that He will give us a pattern in all things.  A pattern I have seen in all covenants and ordinations is the administering authority and then the sealing of that covenant, ordinance, and/or blessing.  We read that in the Kirtland Temple that - 

"...Elias appeared, and committed the dispensation of the gospel of Abraham, saying that in us and our seed all generations after us should be blessed."  (Doctrine and Covenants 110:12)

In my mind, as I read the Abrahamic covenant, knowing that Abraham has already been exalted, that what was dispensed was the keys of exaltation for himself and his seed.  To be exalted, one would have to obtain all temple ordinances including eternal marriage.  Thus in my mind, the keys Elias committed were that associated with temple ordinances and covenants.

With that understanding, Elijah returned with the keys of "sealing" and the work for the dead.  Thus the pattern was established with administration of the ordinance and the following sealing thereof including previous ordinances outside the temple.