This sentence is related to an allusion. According to legend, there was a talented man named Cao Xuequan during the Ming Dynasty. When Cao Xuequan was young, his family was very poor, and his mother raised him by selling sesame cakes. He was also very ambitious. He obtained meritorious service and was sent to work in Guangxi. In the place where he worked, there were some royal aristocrats who, relying on their special status, raised dogs for dog fighting.

In addition to dog fighting, when they are bored, they will deliberately release these vicious dogs and let them bite people on the street. Seeing the people running around on the street, they laughed happily. Cao Xuequan had already heard about such a thing before he took office. When I arrived, I saw that it was exactly as the rumors said.

Cao Xuequan thought that he must find a way to treat these royal relatives. Once, the royal relatives released the dogs to bite the people as usual. There was a scholar who was running slowly and was about to be bitten to death by a dog. At this time, a dog butcher on the roadside rushed out, killed the dog, and saved the scholar.

The royal relatives were very angry when they saw their dog dead. They arrested the dog butcher and the scholar and brought them to Cao Xuequan. They asked Cao Xuequan to sentence him to death for dog slaughter and bury his dog with him. After Cao Xuequan understood the ins and outs of the matter, he believed that the dog slaughterer was not wrong. On the contrary, he also asked the royal relatives to compensate for the medical expenses of the two people.

The emperor's relatives felt that they were losing face, so they secretly bribed the scholar to change his confession. He said that he was playing with the dog that day, and the dog butcher rushed out and killed the dog. For the sake of money and fear of the power of the emperor's relatives, the scholar actually changed his confession. Cao Xuequan knew there was a problem as soon as he heard this, so he tortured the scholar.

The scholar could not resist the torture and told the truth. Cao Xuequan was very angry and said, "They saved your life. Instead of thanking them, you falsely accused them and almost killed them!" So I wrote this couplet: Those who are righteous usually slaughter dogs, but those who are unfaithful are mostly scholars. Judging from the situation at the time, it was really very appropriate.