In this week's Torah portion, Va'etchanan, Moses describes the Revelation at Mount Sinai to the younger generation of Jews who were about to enter the Land of Israel. He describes the voice of G-d, saying: "A great voice, which did not continue." One of the explanations that the Midrash offers for this is that G-d's voice did not have an echo.
The Midrash's answer seems to beg a few questions. How does the absence of an echo indicate greatness? If the voice was indeed strong, would it not have produced an echo? Furthermore, why did G-d perform such a miracle? Since miracles are not performed unnecessarily, why would G-d seemingly change the laws of nature just so that His voice would not produce an echo?
An echo is produced when sound waves hit an object. When the sound waves reach a wall, a mountain, or any such obstacle, they are bounced right back. The only condition necessary to produce an echo is that the object deflecting the sound waves must be strong and rigid. If the object is soft and yielding, the sound will be absorbed and no echo will result.
This physical phenomenon will explain why G-d's voice on Mount Sinai had no echo. When G-d said, "I am the L-rd your G-d," His voice was so overwhelmingly powerful that there was nothing in the world that was strong enough to deflect the sound. G-d's voice actually penetrated the physical world. Every object in the world, from the inanimate to the higher forms of life, absorbed the G-dly voice and was affected by it.
The phenomenon of the Revelation at Sinai is akin to what will take place in the Messianic Era, described in these words: "And the Glory of G-d will be revealed, and all flesh will see." Even our very bodies will be able to perceive G-dliness. So it was at the Revelation. All of physical reality absorbed the Revelation of the G-dly voice.
This is why G-d's voice had no echo. This was not a miracle; the laws of nature were not at all abrogated. It is in keeping with natural law that when a sound is absorbed, no echo is produced. And since the Voice was totally integrated into physical reality, there was nothing that could bounce the sound back. Therefore, the absence of an echo shows the infinite strength of the voice, rather than the opposite.
This phenomenon did not occur only once in the history of the world. Whenever a Jew studies Torah, the holy voice of Torah penetrates the physical surroundings and elevates the world. Our Sages say that in the World To Come, "the very beams of the house will bear witness," for they have been absorbing all the holiness produced when a person learns Torah in his home. (This explains why many tzadikim commanded that their coffins be made from the wood of their desks and tables where they learned Torah and gave food to the poor, for the Torah and mitzvot were "absorbed" by the very planks themselves!)
The power of Torah is such that nothing can stand in its way. The world was created in such a manner as to enable the continuing voice of Revelation to penetrate the corporeal world even today.
