The poem is a short, stark scene: the speaker follows a rope to its end and finds a dead man hanging there. Instead of describing the body, the poem turns to what has been lost. "They" have hanged "all the words he could give" and "all the good," as if the execution killed more than one person. It silenced everything he might have said or done.
The speaker's feeling isn't spelled out, but it comes through in the restraint. There's shock, and also a quiet grief and anger at whoever "they" are. The last line is the strangest: hemp "absolute as a heart." A rope is rough and final, and a heart is warm and alive, so the comparison feels unsettling. Both are certain and unyielding in their own way, and the rope wins.
The mood is bleak, hushed and heavy. The short lines and spare wording leave the reader standing in the silence the hanging has created.