Both are defeated and wounded

A native of Qi, Chun-yu Kun was as humorous as he was eloquent. On one  occasion, Chun-yu Kun came to know that King Xuan wanted to attacked the State of Wei. He went to see the king and said, "In the State of Han, there was a black hound by the name of Han Zi Lu. It was the fastest hunting dog in the world."

Chun-yu Kun continued, " There was a hare named, Dong Guo Qun which was noted for its cunningness. One day, the black hound met Dong Guo Qun and the two had a race. The hare ran fast while the hound was close at its heels. They went round the hill three times. In the end, the hare fell onto the ground as a result of fatigue and the hound also collapsed behind him."

Both of them died as a result.

Chun-yu Kun further added, " An old farmer found them. Since King Xuan intend to attack the State of Wei, both your State and the State of Wei will engaged in a long fight and the people of both sides will be extremely tired with hardship all the way. When Qi and Wei are defeated, the Qin and the Chu will just take our territories like the old farmer."

King Xuan understood what Chun-yu Kun was telling him and the attack was called off.

The saying means that the parties engaged in the fighting will both suffer injuries and sustain losses.