The Name of the Parsha
Vayeitzei connotes having "departed." At the beginning of our Parsha, Ya'akov leaves his home in the Land of Israel, and at the end he returns, having become "exceedingly wealthy." While he was away from home, Ya'akov established most of his family - eleven of his twelve sons - all of whom remained loyal to the path of their father.
And yet ironically, Avraham and Yitzchak who spent all their days in the Land of Israel, both suffered from rebellious children. Why was it that Ya'akov achieved a "perfect complement" of children outside the Land?
While Ya'akov was a tzadik (a naturally righteous person), being the founder of the Jewish people, he also possessed the spiritual advantage of the beinoni and the ba'al teshuva - those who struggle with evil and overcome it.
This element of his personality began to express itself when Ya'akov departed from the spiritually conducive atmosphere of the Land of Israel, and joined Lavan in Charan. Here Ya'akov was forced to immerse himself in a corrupt world, and yet at the same time build a family and conduct his business dealings honestly. This brought to the surface Ya'akov's innate abilities as a spiritual fighter.
The other Patriarchs, by contrast, expelled the negative traces within them rather than fight with them. Thus, Yishma'el became totally disassociated from Avraham as an heir, and likewise Eisav from Yitzchak.
Ya'akov however had the ability to fight evil. His period in Charan, where he fought the external evil of his surroundings, was also a time where he learned how to eliminate any potential evil within his family.
And thus, it was precisely in an unholy environment that he built a perfect complement of loyal sons, because fighting the evil around him taught him how to conquer - and not expel - the potential evil within.
(Based on Sichas Shabbos Parshas Vayeitze 5750)