After the olive orchard parable in Jacob 5, the prophet Jacob comments in Jacob 6:4–
And how merciful is our God unto us, for he remembereth the house of Israel, both roots and branches and he stretches forth his hands unto them all the day long . . . .
In metaphors of this kind, roots are usually understood to be in the past. I puzzled over the use of the present tense here for God’s efforts to save the roots. Now, ‘saving’ the roots could be understood as redeeming the effort and hopes of those ancestors by returning their descendants to the faith they knew and the commandments they recorded. But the Lovely One pointed out a simpler meaning: through the work for the dead, God is saving the past in the present day.
I am not saying that Jacob had any very clear idea of the work for the dead. I am saying that the Book of Mormon is thoroughly steeped in a perspective where it is imperative the fathers’ hearts turn to their children and children to their fathers. Ancestor’s concern for descendants, and for descendants in some way redeeming their forefathers’ rebellion or reviving their righteousness, animate the work.