The theme of"Upon Julia's Voice" by Robert Herrick is the healing power of music and the human voice. The poem focuses on Julia's voice and her lovely song like "lutes of amber." Herrick captures the reader's imagination with his opening line "So smooth, so sweet, so silv'ry is thy voice," emphasizing the power of her voice to calm and sooth.
Herrick reveals that even the "damned" could find peace in her voice and "make no noise," because they are drawn to her "melting melodic words."
Moreover, Julia is never seen throughout the poem, only heard. The fact that she is personally absent from the short poem draws even more attention to how her identity stands solely on the basis of her music and its power to enchant.