As with “There’s something quieter than sleep“, she is confronted with the body of a deceased loved one and is contemplating the grief she feels with the possibility of a joy in the afterlife no living person can comprehend because nobody can comprehend infinite bliss which she describes as “our prize” but seen with “penurious eyes”.
The first line is remarkable in how she manages to show how attached we are to the ones we love with the image of sitting at a wake (“to sit”) as the body lies in repose. If we break the line up we can read it as “the dead we love” and she is saying that love does not stop once someone passes on, but also that there is that feeling of loving that they are dead because they now live in the glorious afterlife.
The second line can work not only as her explaining how the dead “become so wondrous” in that they live in that supernatural realm of infinity. But the use of ‘wonder’ introduces an element of her contemplation of what exactly happens when a person passes on which she sees as a “wondrous” event. Finally she is called back to this life with “wondrous dear” in that not only are the dead still “dear” to us, but you can hear how these might be words of comfort at a wake when someone might be trying to comfort Emily by calling her “dear” as they try to console her which again recalls the moment in “There’s something quieter than sleep” when the “simple-hearted neighbors” try to comfort each other.
Her use of the word “grapple” in the third line is the perfect word because it illustrates her wanting to grasp onto the “lost” – and here “lost” refers both to the dead and those of us left behind (fantastic wordplay) – but to “grapple” is also to struggle, and the line ends unresolved “we grapple” but she does not say with what and it remains a mystery that we cannot comprehend. Hence why we are also the “lost”.
In the fourth line she again uses clever wordplay in her use of “rest” in that the “rest” can refer to the rest of us that “are [still] here” on this mortal realm, but it also paints a picture of the dead resting in their grave – their bodies remain behind while their spirits have moved on.
She then uses a line break to demonstrate the vast and unfathomable gulf between the living and the dead which no words can describe (something she alludes to in “The rainbow never tells me“).
The second stanza is wonderfully complex in how she uses the language of math (logic) to contemplate that which is beyond logic (God / the afterlife). She calls this paradox “broken mathematics” and she uses the words “estimate” and “ratio” (which not only means a proportion, but also refers to pure reason) to describe how we “grapple” with comprehending the “prize” which is the afterlife (which she describes simply as “Vast” after continuing the enjambment of the previous word “prize” thus demonstrating our inability to bring reason into contemplating what this prize might look like) but how “penurious” (poor / lacking) we all are in our ability to actually comprehend “the dead” with our eyes.
Thus we cannot see what lies in store for us in the afterlife because our eyes are too poor in that not only are they filled with tears as we sit at the wake and attend the funeral, but also because we do not possess the ability to comprehend the afterlife; our reason and “mathematics” are too poor an “estimate”.