The figurative meaning of the phrase "poems in their souls" suggests that the dreamers and individuals mentioned in the passage have a deep sense of creativity, imagination, and emotional depth within them. It implies that they possess a profound inner world filled with beauty, artistry, and inspiration. This figurative expression highlights the idea that these people are driven by a sense of artistic and creative purpose, and it characterizes them as individuals who are in touch with their innermost feelings and aspirations.