If Avraham is the clasp of the chain, then Yitzchak is its first link. From his "And the two of them walked together" of the Akeida at the end of Vayeira, through this week's sedra in which we learn of the importance of finding the right life's partner for Yitzchak, and into next week's sedra, we watch carefully as values and personal qualities emerge to teach us what a strong link of the Chain of Tradition is made from. And this is particularly important to us, because we are links in the same chain.
Why does the sedra tell us the story of Eliezer's mission to find Rivka Imeinu, and then repeat the story as Eliezer relates it to Lavan and B'tuel? Partly because the the story is not incidental. It is repeated to emphasize the concerns of a father, the not-so-perfect tactics of the father's emissary, the helping hand lent by G-d in this important quest, the dynamics of Rivka and her family, (and the reaction of Yitzchak Avinu at the end of the sedra). The last part was in parentheses, not because it is less important, but because it wasn't part of Eliezer's repetition of the story.
What we all need to try to be is a combination of different qualities of each of the Avot and Imahot, and of Yosef HaTzadik, Moshe Rabeinu, Aharon HaKohen and various other early links in the chain, with a strong component of the kind of person and Jew we are each capable of being. Add to all this the concern and effort to transmit ones commitment and love of Judaism to the next generation. We must be strong links in the Chain and also help forge the next link.