And it came to pass on the third day as morning dawned, there was thunder and lightning… and the entire nation that was in the camp shuddered.
Why was the giving of the Torah accompanied by thunder and lightning? Was the revelation of G-d Himself not frightening enough, hence requiring a storm to drive home the awesomeness of the moment? The fright caused by physical thunder and lightning seems to pale in comparison to the profound sense of awe that Bnei Yisrael experienced as a result of the G-dly revelation on its own.
Evidently, the dramatic storm at Sinai was not an external cause of fright intended to accompany the giving of the Torah, but an effect and reflection of the awesome revelation that took place then. The physical storm reflected the shocking and earth-shattering spiritual discovery that Bnei Yisrael and the world at large experienced at that great moment.
The Midrash (Tanchuma, Va’eira 15) describes G-d’s revelation at Sinai as the “annulment of the decree” that separated “the higher realms and the lower realms;” i.e., the divide that separated between the spiritual reality and the physical world that derives from it was breached. Until the revelation at Sinai, the “truth” of the physical reality was unquestionable. At the giving of the Torah, that perception was shattered. We were shown that the truth of all existence is not its tangible matter, but its derivation from G-d, the One and Only true Being, who constantly generates its existence.
Now imagine the shock and inner upheaval of a person who discovers that everything he knew until now was a gross distortion of the truth, and that reality is in fact opposite of what he perceived it to be.
Such was the blow that the G-dly revelation at Sinai dealt to the world’s consciousness. Accordingly, the startling thunder and lightning at the giving of the Torah were merely the physical reflection of the spiritual storm that swept and shocked all of existence at that amazing moment.