The Seforim bring that the Shalosh Regalim correspond to the Shloshah Avos, and Chag HaShavuos corresponds to Yitzchak Avinu. What is the connection between Shavuos and Yitzchak Avinu?
We know that Yitzchak corresponds to Avodah [prayer]. Yitzchak specialized in a direct and real relationship with Hashem.
In fact, the Torah describes Yitzchak’s avodah as “Vayeitzei Yitzchak lasuach bisada” [And Yitzchak went out to ‘talk’ to Hashem in the field]. The root of the word lasuach, is ‘seecha,’ which refers to speech, or in other terms, ‘shmoozing.’ The Pasuk is teaching us that Yitzchak’s shmoozing was with HASHEM! He had such a real and direct relationship with Him that even his regular shmoozing was with Hashem.
The above explanation can also explain why Rivka fell off the camel when she saw Yitzchak in the field conversing with Hashem, as she was so in awe to see someone who had that awesome relationship with Hashem.
Perhaps this is one aspect of how Yitzchak corresponds to Shavuos. Matan Torah was the moment when there was the biggest revelation in all of history of G-d to EVERY single one of us. G-d actually talked to the entire Jewish people! Perhaps in the essence of this day, there lies the power to strengthen and develop our connection to Hashem.
May we all work during this Yom Tov on strengthening that relationship via learning Torah, davening, and doing Mitzvos. May we continue to climb in growing closer and closer to the goal of the marriage-like relationship between us and Hashem!