The sentence from Herman Melville's short story "The Lightning-Rod Man" that is an example of allusion is, in my opinion - Who has empowered you, you Tetzel, to peddle round your indulgences from divine ordinations?
Allusion is a reference to a person or a place outside of the text. In this case, Melville is alluding to Johann Tetzel, a Roman Catholic preacher, known for granting indulgences in exchange for money.
