Sun Wukong’s only ever-lasting famous saying is that a man who appreciates kindness but does not repay it is not a gentleman, and will be infamy for eternity. The short 14-character saying is the way of human beings, and it has been widely circulated to this day.

In "Journey to the West", Sun Wukong is a key character. Sun Wukong jumped out of the stone and has infinite abilities. He was once pinned down by Tathagata Buddha at the foot of a mountain because he made a big fuss in heaven. Later, he was saved by Tang Monk passing by. After that, Sun Wukong followed Tang Monk to protect him and repay his kindness.

Sun Wukong has blazing eyes and a golden cudgel. His ability can kill all demons and ghosts and protect Monk Tang from studying in the West. His saying of not repaying a favor is not a gentleman, and this is how he will be infamous throughout the ages.

They passed by Baihu Ridge on their way to obtain Buddhist scriptures. But in Baihuling, there is a white-bone spirit. She knew that Tang Monk would pass by, so she wanted to eat him. In order to eat Tang Monk's meat, she transformed into a village girl, a woman and an old father. But in the first two times, Sun Wukong saw through her because of his sharp eyes and beat her fake body to death. But Tang Seng didn't know. He thought Sun Wukong killed innocent people indiscriminately, so he condemned him. In the third time, the white-bone spirit turned into a white-haired old man again, and was discovered by Sun Wukong again, and was beaten to death. However, Tang Monk wrote a letter of derogation and drove Sun Wukong back to Huaguo Mountain.

When Sun Wukong was driven back to Huaguo Mountain, he told Tang Monk that it would be fine if I went back, master, but I haven’t repaid your kindness yet. But Tang Seng said, "What kind of kindness do I have with you?" Then Sun Wukong knelt down, because I once made a big fuss in the Heavenly Palace and was pinned down by Tathagata Buddha in the Mountain of Two Realms. Without a master, I couldn't escape. If I can't accompany you to study in the West, it will appear that I am not a gentleman and I will be infamy for eternity.

To sum up, Sun Wukong’s unkindness of not repaying kindness and his infamy throughout the ages came about in the episode of White Bone Demon.