During the Warring States period, the scholar Chunyu Kun served as an advisor to King Wei of Qi at the Jixia Academy. When Qi planned to attack Wei, Chunyu Kun advised against it. The king frowned and asked, "Master of Jixia, why do you oppose this?" Chunyu Kun replied, "Have you heard the tale of the dog and the hare that both perished?" The king said, "Tell me, sir."
Chunyu Kun opened the conversation: "Legend has it that the state of Han had a famous hound called Han Lu, the fastest dog in the world, and the state of Qi had a rabbit named Dongguo Qun, the craftiest rabbit in the world. One day, Han Lu chased Dongguo Qun. The two raced around a great mountain three times, then crossed five more peaks. Do you know how it ended?"
King Wei of Qi asked, "Then the rabbit must have hidden itself, and the dog couldn't find it." Chunyu Kun replied, "No. In the end, the rabbit collapsed from exhaustion ahead, and the dog collapsed behind—both dead from fatigue." The king asked with keen interest, "What happened next?" Chunyu Kun answered, "A passing farmer picked them up, took them home, and made a fine meal out of them!" The king pressed, "What do you mean by telling me this?"
Chunyu Kun warned, "Aren't you planning to attack the state of Wei? Though Qi is stronger than Wei, we cannot conquer it overnight, for Wei will fight with all its might. If the two armies become locked in a prolonged stalemate, both sides will drain their national strength. I fear that the powerful states of Qin to the west and Chu to the south will seize the opportunity to destroy both Qi and Wei, just like the farmer who effortlessly caught both the Hanlu hound and the Dongguo hare, reaping the spoils without lifting a finger."
King Wei of Qi, upon hearing this reasoning, abandoned his plan to attack the state of Wei.
Later, the idiom "Both the Dog and the Hare Perish" came to be used as a metaphor for both sides destroying each other.
Source: *Strategies of the Warring States*, Chapter "Strategies of Qi III"
Meaning of the Idiom: Later, the Chinese idiom "犬兔俱毙" came to describe both sides destroying each other.