The poem's grim imagery depicts the exhausting day-to-day sufferings the poor have to navigate. Many of these have to do with simple, constant discomfort.
In the winter, for instance, "the wind rushes through the gaping walls" of the poor's cottages—an image that suggests just how little protection those cracked walls offer, and also subtly suggests that the cottages themselves might seem to gape in helpless horror at what's happening within them. Inside, the speaker observes children "with hunger pinched and cold." Here, the children might be "pinched" in the sense of "gaunt and skinny"—but they also might feel as if hunger and cold are actually pinching them, like mean little elves.
Their parents don't have it much easier. Trying to escape their sufferings in sleep, they find that a "tattered blanket" crawling with fleas doesn’t provide much in the way of warmth, and end up lying awake all night on a "dusty pillow." These images conjure up a bed that offers no rest: here, even the place that should provide "soft repose" is only another small daily torture chamber.
Things get even worse if someone in the family gets sick, the speaker continues—personifying sickness itself as "pale sickness," like a thin-cheeked horseman of the apocalypse. Without the help of a doctor, the poor are helplessly condemned to lie "in a dark room," the living and the dying cooped up in the same "miserable bed." This shadowy moment suggests that the poor die in the dark in more ways than one: their "dark room" also gestures to the way the rest of society shuts these suffering people out of their minds.
Should a poor person survive all these miseries, the speaker observes, they can't exactly look forward to a cheerful, thriving old age. As soon as they can't work anymore, old men whose "rev'rend hoar" (that is, respectable grey heads) should be settled in an armchair somewhere instead find themselves begging on the road, limping along with "halting pace," wearing a "tattered dress of various rags," their "meagre," scrawny cheeks hidden beneath an unkempt and "formidable beard."
The speaker's vision of this frail old beggar—particularly that "formidable beard," a vivid image of involuntary self-neglect—is designed to evoke pity. But pity, the speaker says again and again, is precisely what better-off people can't seem to find it in their hearts to offer their suffering neighbors.