"But man is not born to fail," he said. "A man can be destroyed, but he cannot be defeated."

This sentence is Santiago's inner monologue, which is also the core spirit of the novel. It vividly reveals Santiago's inner world and life pursuit, and it is also a reflection of Hemingway's thoughts and values. This sentence means that the mission of life is to struggle and make unremitting struggle with fate. Although people are born with all kinds of natural and social challenges, perhaps these challenges are strong enough to destroy people's bodies, but as long as one maintains a strong fighting spirit and the spirit of not giving in in the face of any difficulties and obstacles, one will always be a winner. Although Santiago, the old fisherman in the novel, failed to save the marlin in the end, he showed unparalleled strength and courage in the process of fighting the shark, without losing human dignity, and was a spiritual winner.

To examine the ability to understand the methods of portraying characters in the works and grasp the plot of the works as a whole, the most distinctive famous saying of the old fisherman Santiago is the clue that runs through the whole text, which is the main theme of the whole text.