The poem pictures ravens in the cold season, loitering and hoping for an ox to die so they can feed on it. The speaker calls this "dead hope," a pun that works two ways: the hope is for something dead, and it is also close to hopeless. The ox would be a rich find, "full of news and folly," a strange phrase that makes the carcass sound like a gossipy, foolish person, or like a whole world of stories the birds could swallow. It would last them the winter.
The final lines turn from food to night. The ox is also "full of midnight," as if the dark itself were something to be eaten or settled into. The ravens bed down in something "thin as a purse," which suggests how little comfort and money there is. The speaker doesn't judge the birds. The mood is lean, dark and wry, with hunger and hardship handled in a dry, almost playful tone.