The Torah tells us that Yaakov was afraid and he had fear and Rashi comments that, he was afraid he would get killed and he feared that maybe he would kill others. Many commentaries ask, we learned in the previous portion that Hashem promised Yaakov that he will be with him and watch over him, why was he afraid ? It is well known that the Chozeh of Lublin was extremely humble, and he once expressed about himself, that even if he heard from G-d directly, that he is a Tzadik (pious man), he would believe that it was true just for that second, but a second later he would be worried maybe he lost his greatness. This helps understand the way Ramban explains the fear of Yaakov. Ramban says that great people are constantly worried that they shouldn’t lose their level of holiness and that maybe according to the talents and strengths they were given, they didn’t do enough. So although Yaakov received a promise from Hashem that he would watch over him, maybe, he feared he was no longer worthy of the blessing.
The Chidushei Harim says that Yaakov was praying not for himself, but for the future generations and his fear was for his descendants when/if they would be in this situation they should be saved from the evil forces who want to destroy them. This has been proven over and over again. Unfortunately in many generations there were/are forces who thought/think they will erase the Jews from the face of the earth and Hashem saves us, as we read in the Hagodo, on Pesach, Shebchol dor vodor omdim oleinu lichaloseinu, v’Hakodosh Boruch Hu Matzileinu miyodom.
One more idea I’d like to share with you regarding the outlook on life of Yaakov verses the outlook of Eisov. In Bireishis 33/5 when Eisov finally reaches Yaakov he saw the women and the children, and said “who are these to you”? And Yaakov replied, “the children which Hashem granted me”. The Divrei Shmuel of Slonim explains the dialogue between the two. Eisov saw Yaakov has four wives, and he thought to himself, this is my world, how does it come to a holy man like Yaakov ? Yaakov’s response was the purpose of marriage to these women was to have these children. It is known that a Baron once asked the holy Rebbe of Rizhin what’s the difference between me and you, I eat and drink and so do you, I have a wife and children and so do you. The difference, replied the Ruzhiner, is that you live because you want to eat and drink, I eat and drink because I want to live. You have children because you have a wife, I have a wife because I wanted to bring children to the world. It is all about putting things into perspective.