What does the author believe makes a spiritual narration effective, as described at the start of Chapter 21?

At the beginning of Chapter 21, the author reflects on the qualities of an effective spiritual narrative. He believes that the speaker's words are pointless if they do not produce a profound physical and emotional reaction in the listener. He considers a narration successful only if the listener "sway upon hearing them" and the "hair on the body... stand on end." He states that stories are futile if they do not delight the listeners, cause their throats to choke up with emotion, and bring tears of love and joy to their eyes. This perspective from Chapter 21 underscores his belief that the purpose of such stories is to evoke a deep, visceral, and transformative spiritual experience.