It tells you: "You are going to die. Here is what happens next. Now, knowing that, how will you live today?"
By understanding the 28 hells, we learn to practice the 10 virtues (Yamas and Niyamas). By understanding the journey of the Preta, we learn to respect our ancestors. By understanding the court of Yama, we learn that the universe is perfectly just. garud puran part 1
Lord Vishnu tells Garuda that the Preta (ghost) has no physical mouth to eat, but it has a subtle tongue that craves sustenance. When the son offers a pinda made of barley, black sesame, and rice, it creates a subtle energy body for the ghost. It tells you: "You are going to die