The Torah says that Jacob was afraid of Esau, even though Hashem had promised him, "I will be with you and protect you." That promise was given when he had just left the home of Isaac and Rebecca, and was under their influence. Now, however, he had been with the wicked Laban for twenty years, and Jacob was worried that he might have been influenced by Laban's sinful ways, and he no longer merited Hashem's protection.
We must always be on the alert that we are subject to the influence of our environment. We may feel secure when we regularly attend the meetings with which we are familiar. But if we go to another location, whether for business or vacation, we may not have the protection to which we have been accustomed.
The enemy is cunning, baffling, and powerful, always looking for a weak spot in our defenses. When we leave a secure environment, we must increase our defenses.