Toldos and Vayeitzei combine to present us with three stories about the Avos and wells: Avraham digs wells, Yitzchak reclaims those wells after they had been clogged by the Plishtim, and Yaakov removes a rock from on top of a well.
Chazal already point out the many "shidduchim" realized at a well (i.e. Rivka and Yitzchak via Eliezer, Rachel and Yaakov, and Tzippora and Moshe), and the Ramban discusses the significance of the three wells that Yitzchak attempted to reopen and shows them to be symbolic of the future batei mikdash. But what lies in the different tasks performed by each of the Avos? They share the common undertaking of making well-water accessible, yet each of them does it differently.
It is obvious that a well reflects the flow of "Elokus" [divinity] into the world - it is a seemingly infinite flow in the sense that wells seem to have an unlimited supply of water, as opposed to cisterns and reservoirs. It is, so to speak, a gateway to the infinite; not that we have full access to the infinite, but that it does become more accessible to us, and is the source of life for all and everything.
The world seems devoid of the divine presence, and it is incumbent upon man to breakthrough to it. Each of the Avos engaged in bringing that light into this world. Each - based on his particular kochos - perceived the challenge differently and added another approach to allowing that light into the world.
Avraham Avinu came into this world at the end of the two thousand years of tohu - the darkness of sin and idolatry. Hashem had simply "ceased to exist" for the majority of humanity, and Avraham needed to actually bring God into this world. The very idea of one god, who is incorporeal, creator and source of the good, was an idea that needed to be "created". Avraham "dug the well" and introduced Elokus into the world. This is the hallmark of ahavas Hashem: a constant drive to let the world feel the divine presence. [See Rambam in Sefer HaMitzvos, aseh #3.]
Yitzchak Avinu is seen as the embodiment of yirah. While Avraham's middah is a proactive one, Yitzchak's nature is more given to guarding against evil. It is true that Avraham had dug a well and water flowed into the world, but this well was slowly dying from the minute it came into existence. Dirt and silt were accumulating, and jealous neighbors were waiting to stuff them up entirely. It is only the constant cleansing and removing of silt that will keep the wells from disappearing. This is the essence of yirah: a nonstop standing on guard so that evil does not choke out the good that exists already.
Yaakov's attribute, however, is deeper still. He brings into the world the understanding that the good always existed and exists, and evil does not and can not eradicate this good. What can happen is that the divine presence may be covered up, and we become oblivious to it. Yaakov himself realized it when he slept in Beis El and proclaimed that, "Indeed there is Hashem in this place, and I was but oblivious to it." Yaakov's perspective meant that one simply has to remove the covering and see that the well is as pristine as it ever was.
Klal Yisroel inherited all three of these perspectives from our Avos: the burning drive of ahava to bring the divine presence into this world, the caution of yirah to guard against evil seeping in and polluting that divine light, and, above all, the realization that in truth the divine light is never extinguished and if one but removes the covering one sees the light as it was.
This is the basis for the ruling that, "Yisroel, afa al pi she'chiti, Yisroel hu - a Jew, even if he sins, he is still a Jew." The divine spark that Yisroel (Yaakov) fathered in us eternally remains unextinguished regardless of how many layers cover over it.