The title borrows the old phrase "keeping the wolf from the door," meaning to stave off poverty or hunger. Here the wolf seems to stand for something wilder and more threatening, and the poem's first image is a strange bargain: we pay it off with "a fine house in heaven." In other words, we hand over promises of a reward in the afterlife to hold fear at bay now.
The speaker then pleads, "Save me from nature— / not a sister / but a servant." That line flips a familiar idea. Nature isn't a gentle family member to be loved, but something meant to serve us, and the speaker wants protection from it either way. The tone is uneasy and a little bitter.
The last lines are the most unsettling. "All night it drums / in our ears" suggests the wolf, or the fear it stands for, never goes away. The mood is anxious and sleepless, with the poem's short, clipped lines adding to the tension.