Eved means Kabalas Ol, and the Torah in this case is Osiyos Hachakika, so the Bittul is on the level of Chakika. This is why this story is chosen to demonstrate Hashem’s love for ‘avdei batei Avos’. Page 185.

The story of this marriage is very important and it was achieved by giving (a nose ring) Mitzvos and (Two bracelets that correspond to the Aseres HaDibros) Torah on the level of Chakika (engraving) Page 184.

Even Parshas Toldos (until the next Shabbos) is connected to [the Shabbos before:] Chayey Sarah. The marriage of Yitzchok and Rivka is the example chosen to demonstrate Hashem’s love for the Avos because it represents the marriage of Hashem and Yidden . The kidushin is achieved through the nose ring (Mitzvos, like machatzis hashekel) and…