It is clear that Liu Bei, Guan Yu, and Zhang Fei are extremely lucky to have found and pledged their lives to one another when they did. Because the oath they swore cannot be broken by anything but death, the three men are bound to each other no matter how profoundly they disagree. And because they cannot sever the tie that binds them, they are unable to disconnect themselves from the world around them in such a way that would result in a fate similar to Jian and Sun Ce's. When Guan Yu and Zhang Fei encourage their eldest brother to once more go to war with Cao Cao, Liu Bei is able to think about more than just his reputation, and he preaches caution; he doesn't want to risk the lives of his sworn brothers or their allies.