http://revach.net/article.php?id=5337

Section: Moadim   Category: Shavuos
Rav Chaim Zaitchek - Why Was the Satan the Only One to Miss Matan Torah?

The Medrash (Shmos Rabba 29:9) says that when Hashem gave the Torah the birds did not chirp, the oxen did not bellow, the Ofanim did not soar, the Serafim did not say "Kadosh", the waves of the sea did not crash, no creature spoke. The world was completely silent as Hashem said "Anochi".

The gemara (Shabbos 89a) says that after Moshe took the Torah from Shamayim, the Satan asked Hashem, where has the Torah gone. How can it be that the entire creation stood still as they witnessed the giving of the Torah, yet the Satan, who is a Malach and is privy to what is happening in Heaven, completely missed the entire episode? All the nations of the world heard it in four languages as the foundations of the world shook, and the Yetzer Hara didn't notice?

Rav Chaim Zaitchek elaborates on Tosfos's answer and explains that the Torah is light and during Matan Torah the light of the Torah flooded our otherwise dark world. The world shone like never before and never again. Every creature was exposed to this light and saw the truth for a single moment in time. However the Satan is the epitome of darkness, as that is his entire being. His purpose is to cast darkness on the world and cover the light of the truth. This being, so no light, however bright, can turn on the light for the Satan, for then he would cease to be.

When a person casts himself in the dark, even if the truth stares him in the face he won't see it. It is up to us to step out of the darkness and allow the light to shine in. Our goal on Shavuos is to open our eyes and bask in the beauty of the Torah, its commandments and its way of life. Once we see the light, we will think twice before turning back. דרכיה דרכי נועם וכל נתיבותיה שלום