According to Chapter 21, what makes a spiritual story effective, and how should a listener ideally react?

Chapter 21 sets a high standard for both the storyteller and the audience in a spiritual context. It states that a narration is considered futile if the listener is not deeply moved by it. According to the text, an effective narration should cause a profound physical and emotional reaction in the listener. Specifically, the chapter mentions that upon hearing the words, the listener should sway, the hair on their body should stand on end, their throat should choke up with emotion, and tears of love and joy should flow from their eyes. The absence of such a heartfelt response indicates that the speaker's words have ultimately "gone in vain."