The poem is a short, strange fragment of a funeral, and it works by suggestion rather than explanation. We get a church, a speaker singing a psalm, and an odd detail: the psalm is sung "to the stairs," not to a congregation or to God. That small shift makes the scene feel lonely, as if the usual ritual of mourning has gone slightly off its hinges.
Then the image turns surreal. A "newly drowned body" arrives to dance, which suggests the dead person is not simply gone but somehow still moving, still present. The last lines, "out of her being / out of her us," are the most puzzling. Judging by the wording, the dancing seems to rise out of the woman herself, and perhaps out of the bond between her and the people who loved her. The speaker never says "I'm grieving," but the mood is dreamlike, eerie, and tender, a blend of sorrow and odd, wavering wonder.