First, Zhao Yun advised Liu Bei. It means that the traitor is Cao Cao, not Sun Quan. If Wei is defeated, Wu will serve itself.
The second is to record that "ministers remonstrate more".
Third, Liu Bei was furious and didn't listen.
In fact, is there any reason for Liu Bei to attack Wu? Yes And very full. The first point is the same as Gaozu. Anyone who went back to his hometown to read Historical Records remembers that Liu Bang took a group of Jiangsu people to Shu. His main force is Pei County. This is the core of leadership. So after Liu Bang arrived in Shu, most of the troops fled. Because China people have been homesick since ancient times. This is a tradition. You can't change it. The route that Liu Bang took later was the route to his hometown. Because of this, morale is particularly high. This is human nature, it is human nature. You can't violate. Can only follow, you see Liu Bei is the same. The core of his leadership is Jingzhou Group, and the main backbone of the soldiers is Jingzhou people. The most loyal person in the army must be the Jingzhou person who has been with him for the longest time. For this group of people. It is necessary to go back to my hometown. Including Fu Tong and others who were later captured and killed, were all from Jingzhou. They are loyal to Liu Bei and would rather die than surrender. Many of the leaders of Liu Bei's crusade were from Jingzhou. These people died in Yiling and in the countryside. Buried in my hometown is immortal. So Liu Bei insisted on the crusade, just like Liu Bang left Qin Guan. It's all about going home That's understandable.
The second point is why Liu Bei did not save Guan Yu when he died. My opinion is that Liu Bei and Guan Yu are actually related by blood. Liu Bei's battle in Hanzhong has just passed. Need a rest. Guan Yu is also in full swing. Just contains. But don't forget. According to the Records of the Three Kingdoms, Cao Cao refused to withdraw his troops from the Western Front at this time. It can be seen that his defense against Liu Bei is very tight at this time. Therefore, it is most likely that Liu Bei intends to use Guan Yu to disturb the Central Plains and Cao Cao to transfer troops to Guanzhong, leaving Qinchuan to occupy Guanzhong, Yong and Liang on the surface. Gaozu's work is half done. Because their plan has been going well. On the eve of the cooperative war. Is strictly confidential. Therefore, there won't be too many people to contact between Liu and Guan. This led to the reason why Liu Beifang couldn't get the information when Lu Xun closed the gorge. Before Guan Yu's downfall, I think Liu Bei had a plan to leave Qishan and March into Guanzhong. At this time, Chengdu will certainly shrink its troops and prepare for the battle. But Guan Yu failed in vain. Soochow stabbed him in the back. Let Liu Bei attack the army all the way. So the next choice is only two, either cutting Wei or cutting Wu. Yi Zhongtian said that Liu Bei should rest, which is wrong. Because half the country is lost, the rest is waiting to die.