These are the descendants of Yaakov

 

וַיֵּשֶׁב יַעֲקֹב . . אֵלֶּה תֹּלְדוֹת יַעֲקֹב  בראשית ל"ז, א

 Yaakov dwelt... These are the descendants of Yaakov.

 (Beraishis 37:1) 

The Torah describes Eisav's settlements and his descendants only briefly, since these were neither prized nor important enough to elaborate upon… It describes in detail Yaakov's settlements and his descendants, and all the events that brought these about, since their importance before G-d warrants dwelling upon them at length. …

This can be compared to a pearl that falls into the sand: A person searches in the sand and sifts it with a sieve until he finds the pearl. Upon finding it, he casts the pebbles from his hand and keeps the pearl. —Rashi Between Pebbles and Pearls Rashi's parable of a person searching for a pearl lost in the sand also alludes to the Jewish people's task in the lands to where we have been exiled: to sift through "the settlements of Eisav."

The search for the pearl symbolizes our mission to find the holiness—the G-dly meaning and potential—hidden within the mundane world with which we are engaged. This explains why Rashi includes a detail in the parable that seems otherwise superfluous. To illustrate that the surrounding stuff is of little value in comparison to the object of the searcher's desire, why was it necessary to note that upon finding the pearl one "casts away the pebbles"?

It is self-evident that once one has a pearl in his hands, he loses all interest in the pebbles and sand he was sifting through to find it! By mentioning this detail, however, Rashi teaches us that "casting away the pebbles" is a crucial part of our mission in Exile. In order to elevate (and be elevated by) the sparks of G-dliness found in the material world, we must be certain that what appeals to us is not "the pebbles"—the setting of physicality in which those sparks lie hidden.

Otherwise, we will be drawn in to the material world instead of drawing out its good. Only after we cast away any personal interest in "the settlements of Eisav" can we successfully extract and benefit from "the pearls," the spiritual wealth hidden therein.

 —Likkutei Sichos, vol. 15, pp. 306-307