"The Eve of St. Agnes" is so rich in narrative, theme, and figurative language that many quotes from literature would relate to it. Here is a quotation from German playwright and poet Friedrich Halm (1806-1871). It appears in Ingomar the Barbarian and is translated here by Maria Lovell:
What love is, if thou wouldst be taught,
Thy heart must teach
Two souls with but a single thought,
Two hearts that beat as one.
These lines capture the passionate love Madeline and Porphyro find in each other on St. Agnes' Eve. When they are united, Porphyro becomes a part of Madeline's dream. Their hearts do beat as one. At the conclusion of the poem, Madeline and Porphyro escape before others in the castle can keep them apart. They have "but a single thought" as they flee into the darkness, "away into the storm"--to be together, no matter the risk.