What is the symbolism of "magic strings" in the book, The Magic Strings of Frankie Presto?

Frankie's magic strings is a major symbol of the novel, representing music's power to save lives - both literally and figuratively. Whenever Frankie channels his God-given gift for music instead of chasing celebrity status, the magic strings are active. Every time the strings turn the color blue after saving a person's life, Frankie had been using his music: he played lightning-fast to distract Aurora's attacker; he saved Hampton by offering the racist doctor a performance; he physically uses his guitar case to shield young Ellis from a shrapnel blast. The magic strings are a symbol of the novel's theme of “music as salvation,” showing how it can save people in both extreme and everyday ways.