The speaker is writing about a man, Lord Sand, who has left the sea for the fields, and the poem reads like a worried, bitter report on him. At first the speaker is unsure, suspecting that the move was "done for a joke" and that something is wrong with him. Then the rumours pile up: he will lead "in the darkest manner," he may be hoarding money, he is angry and blind to his own faults. The image of "an axe white with light" sits oddly in the warm weather, quietly suggesting threat.
The final lines are the most striking. Lord Sand has "no face but a grave," and the speaker refuses to call him a brother. That reads as a break, a decision to cut ties. The closing resolve to "stand on my own legs / or fall" sounds both defiant and a little frightened. The mood is uneasy and guarded, with disgust, grief, and stubborn independence all mixed together. Because the poem never explains what Lord Sand has done, the menace feels larger and harder to shake.