Symbolism, Imagery, Allegory
For a book about knights and swords and stuff, there's an awful lot of healing going on. (Okay, maybe that's not so surprising.) Some of this healing is essential to the plot, such as when Alanna boots the Sweating Fever that almost takes Jonathan's life. Some of it is tangential to the plot, like when Alanna uses her Gift to speed up the healing of her broken arm so she can resume learning to fight in order to kick Ralon's butt. But put it all together, and you've got one major symbol.
Healing first appears on our radar when Maude is cutting Alanna's hair so that the twins can perform their great switcheroo. Maude tells Alanna: "if you want to pay for those lives you do take, use your healing magic. Use it all you can, or you won't cleanse your soul of death for centuries. It's harder to heal than it is to kill. The mother knows why, but you've a gift for both" (1.57).
Clearly, it's kind of anomalous that Alanna has the capability to both kill and heal. And the idea that Alanna has to heal in order to sort of repair her karma is pretty interesting. In other words, the book is kind of asking us: "Hey, what are you doing to repair the damage you do to those around you?"
Maybe you haven't chosen a profession that involves killing people, but it's still an uncomfortable question, right?