In the poem the speaker says, "The Carriage held but just Ourselves –
" At the very beginning of the poem the speaker personifies Death. When she says, "Because I could not stop for Death - He kindly stopped for me". This idea that Death stops for the speaker, personifies Death and makes him a character in the poem. This means that "Ourselves" refers to the speaker and Death.
Some people have argued that since Death is personified, so is Immortality and therefore Immortality is also riding in the Carriage with the speaker and Death. However, this is not a widely accepted interpretation.
