What does the text say about the power of karma and destiny, especially in relation to a Guru's abilities?

The provided text from Chapter 2 explains that every living being is governed by the system of Karma, and destiny is considered irresistible. This is illustrated through the story of a man whose friend's only son died from a fever, despite his Guru being present. This event caused the narrator to become very restless and question the utility of a Guru, wondering aloud, "What can Gurus do against Karma?" The text suggests that whatever is destined to happen, or "written on the forehead," will occur, leading to the conclusion that even a Guru's presence might not alter the course of powerful past karma.