Who is Jealous Souls from The Interior Castle and what is their importance?

Teresa warns those of her sisters who might receive spiritual favors to remain quiet and humble about them, both in order that they not allow their pride to interfere with their own worship and so they not cause those of their sisters who might be tempted to accuse them of falsehood or putting on a dramatic show to stumble into those temptations. She encourages the sisters never to compare their experiences with another person's, but walk through their own experiences faithfully attentive to its lessons.