In literature including stories, novels and poems the theme refers to the underlying message in a literary work, this means the message the author of the poem wants the reader to understand which is usually linked to some universal aspect of life and expressed through different elements in the poem or literary work. Considering this, if you are searching for the underlying or deep message that two or more poems share and that the author is trying to convey through the text it means you are trying to find the theme of the poem as it is the theme the literary element that deals with the main or underlying message of literary works.
