We shift all the way back over to the left side of the page after moving to the right for "trembled." Notice that we get something that, in a poem about the burial of an old woman, seems a little out of place—joy.
But if we think about it, we can see that "joy for the living" isn't that out of place. In fact, this takes us back to one of our explanations for why the husband's dust was trembling. We can imagine that, when he died, he was glad that his wife remained alive, still living, still experiencing the joys and wonders of life.
When she was lowered down, he may have been trembling in this very same sadness that she is no longer experiencing the joy of living.
Yet this line doesn't say anything specific about the old woman or her husband. It just talks about joy for the living in general. This line could be said to be in juxtaposition, or contrast by close placement, to the death in the other lines.
We encourage you to let your imagination wander—think about the lives that you have joy for, and what is joyful in your life. For whom would your dust tremble?
is sorrow for the dead.
This line wraps up the poem by defining the line before. We had a brief reprieve from the sadness of the poem in line five, which mentioned joy for the living, but now we are plunged back into sorrow (plus more indentation). It might seem contrary to define joy using the word sorrow, but if you think about it, you can see that this definition is kind of cool.
Look at the way the words line up, with joy and sorrow occupying one place in both lines, and living and dead taking up another. Thus, when life turns to death, joy turns to sorrow. The glee and glory of life is what makes death so sad. If life wasn't worth rejoicing over, then, well, death wouldn't be worth mourning.
So this line seems to end the poem on a pretty glum note, but we ask you to keep your chin up. If you chew these few lines over in your head, you can see that there is as much respect for the joy of the life of this old woman as there is sorrow for her life in this poem. This poem tries to tell us that great sadness means there was once great joy, and that joy should be celebrated as the life is mourned.
There are so many ways to read this poem that it's important to consider them all, but, ultimately, read the poem in the way that speaks most to you, whether that way leads you to despair or to solace.