The Knife Sharpener

My dad is dead. Wu Zuo said that he lost his footing and fell into the water. My father has been fishing in the river since he was three years old, and his water skills are better than anyone else. He was a knife sharpener, but before he died, he left me an account book that no one could understand, and a grudge that had no place to settle. The account book reads: In a certain month of a certain year, a knife was given to someone on credit, and what words were left behind. People who lend knives on credit go around the streets and lend knives on credit without charging any money, leaving only a prophecy. On the day when the prophecy comes true, he will come to collect the bill. What you receive is not money, but fairness. My father died on this account. My name is Shen Qi, the son of a knife sharpener. I'll collect dad's debt. After the knife is sharpened, the person must stand up straight. Someone speaks and someone responds.