"Prophet! said I, 'thing of evil—prophet still, if bird or devil!—
By that heaven that bends above us—by that God we both adore—
Tell this soul with sorrow laden if, within the distant Aidenn,
It shall clasp a sainted maiden whom the angels name Lenore—
Clasp a rare and radiant maiden whom the angels name Lenore—
Quoth the raven 'Nevermore'."
Here, the speaker invokes "heaven" and "God" to lend weight to his desperate plea for knowledge about his deceased love, Lenore. This references the Christian belief in a higher power and an afterlife. The speaker implicitly trusts in a God who could possibly reunite him with his lost love in "Aidenn," a word Poe uses to refer to the biblical Paradise.
The raven's reply, "Nevermore," in the context of this invocation, further amplifies the sense of despair and finality. The speaker's faith, even if fleeting, is cruelly dashed by the raven's chilling response.