What does it mean to stab a tiger when it hurts it?

All you have to do is wait for the right time to assassinate the injured tiger, that is, to win two tigers at one fell swoop.

Source: "Warring States Policy Governing the Stinky Tiger of Zhuangzi"

Original text:

If there are two tigers fighting for people, Zhuangzi will stab them. The words of control: "tiger, ant; People are willing to take the bait. Today, two tigers are fighting for people, the little one is dead and the big one is hurt. Stabbing a tiger while waiting for an opportunity to hurt people is equal to killing two birds with one stone. Stabbing a tiger is effortless, but it has the name of stabbing two tigers. "

Translation:

There are two tigers fighting for a man. Although Zhuangzi wanted to kill them, he said, "The tiger is a greedy and cruel animal, and man is its most delicious food. Now that two tigers are fighting for one person, the weak tiger will definitely die and the strong tiger will definitely be injured. All you have to do is wait for the right time to assassinate the injured tiger, that is, to win two tigers at one fell swoop. I didn't pay the labor of stabbing a tiger, but I have the reputation of stabbing two tigers. "

Extended data:

During the Warring States period, a war broke out between Korea and Wei for more than a year, and there was still no winner. King Hui of Qin intended to send troops to intervene. At this moment, Chen Ke, the envoy of Chu, arrived. King Hui of Qin knew that Chen Ke was very learned, so he asked him for advice. Chen Yi told the story to Qin.

Chen said to Qin: "Now the long-term war between North Korea and Wei will inevitably lead to the demise of the weak country and the great country will be greatly weakened. At this time, if you follow the trend and defeat the weakened forces, doesn't it mean destroying the two countries at once? " King Hui of Qin listened to Chen Ke's advice and really won. According to this story, later generations take "both lose" as an idiom, which means that both sides of the struggle suffer losses.