At the beginning of Chapter 21, what does the author say makes a story powerful, and how does this connect to his description of Sai Baba's teaching style?

In the introduction to Chapter 21, the author defines a powerful narration as one that deeply moves the listener. He states that words are 'in vain' if the listener 'does not sway upon hearing them' or if their hair does not stand on end. He believes a narration is 'futile' if it fails to delight the audience and evoke emotions so strong that 'the throat does not choke up with emotion, and tears of love and joy do not flow from the eyes.' The author then directly connects this ideal of impactful communication to Sai Baba, whose own methods he praises. He describes Baba’s speech as 'captivating,' His method of instruction as 'extraordinary,' and His actions as 'innovative,' implying that Baba embodied this very principle of profound, heart-touching communication.