The poem "A Letter From Heaven" is inherently a religious poem. The form of the poem is a letter to loved ones from someone who has passed away and is now in heaven; this is a Christian concept.
The religious content of the poem is not overbearing; however, most versions of the poem include the words "heaven" and "God." The poem explores the peace that a person finds after passing. It is written from the point of view of the deceased explaining to his family that he is okay. It is meant to comfort those mourning the deceased.
There are several versions of "A Letter From Heaven," with the majority of them credited to an unknown author. It is common for people to personalize this poem as a eulogy or tribute to a deceased loved one.