Fear and Distress

Then Jacob feared greatly and was distressed and he divided the people that were with him, and the flocks and the camels into two camps. Genesis 32:8

He was afraid lest he be killed and he was distressed that he might kill someone.

                 Rashi (quoting Breishit Rabba and Tanḥuma)

Had Jacob been forced to kill Esau or his men, he would have been acting in self-defense; hence it would have been permissible. The Midrashim teach us the greatness of Jacob, who was distressed at the mere possibility that he would be forced to take the life of an enemy who would be ready to kill him without qualms

“Then Jacob feared greatly … and he divided the people ... into two camps.” Perhaps the verse hints that it was the necessity to divide into two camps, creating a lack of unity, which fueled Jacob’s fear that Esau would be able to overcome him.

 My brother added the insight that Jacob's fear that he and his camp might be killed by his brother did not overcome his distress at possibly being forced to kill his enemy in self-defense. Thus, in the hope of preserving life, his own and his brother’s, Jacob risked creating a lack of unity in his own camp, though this fueled his fear that Esau would be able to overcome him.