What does it mean if two people refuse to give up?

The meaning of "if two people refuse to give up, the fisherman will get the bird":

Neither the snipe nor the clam would let them go. As a result, a fisherman caught them together. This sentence comes from "the snipe and the clam fight", which tells the story that the snipe and the clam fight, contain each other and give in to each other, and finally let the fisherman profit from it.

The original text of "the snipe and the clam strive for each other"

Zhao cut Yan, and Su called Yan, saying, I have passed Yishui. When the clam is exposed, the snipe pecks at its meat, and the clam closes and grips its beak. The snipe said, "If it doesn't rain today, there will be dead mussels tomorrow"! The clam is also called the snipe: "If you don't come out today, you will die tomorrow"! If the two men refuse to give up, the fisherman will get the bird. Today, Zhao cut Yan, Yan and Zhao supported each other for a long time, in order to harm the public and fear the benefits of fishermen. So, I hope your majesty is familiar with it! "Hui Wang said," good ". It's a stop.

Translation:

When Zhao was ready to go to war with Yan, Su said to him, "Today, when I crossed Yishui, I saw a clam shell coming out of the water to bask in the sun, and a snipe came to peck at its meat. The mussel immediately closed its mouth and clamped the snipe's mouth. The snipe said: If it doesn't rain today and tomorrow, there will be dead mussels. The mussel also told the snipe that if you don't take it out of your mouth today, you will starve to death tomorrow. Neither of them would give up on the other, so a fisherman caught them both together. Now Zhao is going to attack Yan. If there is a long-term disagreement between Yan and Zhao, it will not be good for both sides. I'm worried that the powerful Qin will become a fisherman for nothing. So please reconsider. Zhao said to him, OK. So he stopped sending troops to attack Yan.

The implication of "the snipe and the clam contend";

This is a story in which snipes and mussels compete with each other, but let fishermen profit from it. It warns people to weigh the gains and losses, don't just think about things that are beneficial to them, be humble to each other, take a step back and broaden their horizons, and blindly hold each other's eyes, which will often take care of one thing and let others take advantage. Be a man, learn to be patient, otherwise both sides will benefit only the third party.