Five lines, and the poem already sets up a courtroom. "Full vs. empty" is the shorthand of a legal case, and the first line obliges with "summons". Joy here is not a mood that drifts in or a reward for good behaviour. It is an official notice that you are expected to turn up. What you are summoned to is oddly physical: "to dine on fat". The word is blunt and a little greasy. It means richness and surplus, and perhaps a touch of indulgence, and the poet doesn't soften it into "feast" or "banquet". Joy, on this account, is appetite answered, and refusing it is a kind of failure to attend.
The second stanza introduces the opposing party. "I fear the children of discontent" is a striking way to put it. Discontent is cast as a parent and these people as its offspring, born into the condition rather than passing through it. The speaker says "fear", not "dislike" or "pity", and the poem leaves open whether that fear is of them or for them, or of becoming one of them. What they do is strangely modest: they are "busy setting papers in order till late". There is no villainy in it, only diligence. But the phrase "setting papers in order" is the poem's sharpest irony. It suggests ledgers, forms and files, a life tidied rather than tasted. The phrase also resembles the idea of putting one's affairs in order, which hints at endings, though that is an inference from the wording. The summons to dinner goes unanswered because the guests are at their desks.
The poem's shape carries the argument. It has no rhyme and no punctuation, and it opens in lower case, as though mid-thought. The first stanza is two short lines, compact and declarative like a proverb. The second runs to three longer lines that sprawl across the page, and the sprawl is the point. Joy is brief and dense, while discontent drags on. The enjambment helps. "Till late" ends its line, so the reader waits for what follows, and the next line delivers "night". Read quickly, "late night" is a plain phrase, split across the break as if the working day were being stretched past its limit.
Then comes the poem's most inventive moment: "night new-laced with night". The sound is a repeating long "i", and the logic loops back on itself. Lace can mean threading, as with a shoe. It can mean decoration, as in fabric. And it can mean adulteration, as in a drink laced with something. All three seem to be in play. The night of the clock gets a second night woven through it, and the doubling suggests darkness piling up with nothing else added. Compare the first stanza, where joy is paired with something different from itself, fat, and the metaphor adds a new idea. In the last line the noun can only repeat itself. That tautology is a small image of emptiness, a thing described by nothing but itself.
Hearing the poem aloud shows the contrast in its sounds as well. The first stanza is full of firm, short syllables: "joy", "dine", "fat". The second leans on softer, slipping sounds, "children", "discontent", "papers", "order", and ends on the almost hypnotic repetition of "night". The language goes from solid to blurred as the people it describes lose their grip on pleasure.
What makes the poem worth reading is how much it does with so little. It doesn't lecture about gratitude or tell us to seize the day. It gives us a summons, a meal and a pile of paper, and lets us decide which table we would sit at. The title's "vs." makes it a contest, but the verdict is tucked inside the images. The poem also avoids easy moralising by admitting fear. The speaker doesn't stand serenely above the paper-shufflers, which suggests that the pull of order and duty and one more hour of work is real and a little frightening. Joy, by contrast, is shown as something you have to answer, and you can answer it only by putting the papers down.