Analysis of A Fragment

They say that poison-sprinkled flowers
Are sweeter in perfume
Than when, untouched by deadly dew,
They glowed in early bloom.

They say that men condemned to die
Have quaffed the sweetened wine
With higher relish than the juice
Of the untampered vine.

They say that in the witch's song,
Though rude and harsh it be,
There blends a wild, mysterious strain
Of weirdest melody.

And I believe the devil's voice
Sinks deeper in our ear
Than any whisper sent from Heaven,
However sweet and clear.