Perek Shira: The Rivers Sing, What About The Mountains?
During the week leading up to Shavuos as my little son was singing the Har Sinai song, I was wondering why in Perek Shira the mountains don't say Shira? The next day I said Perek Shira and when saying the Shira of the rivers, "Neharos Yimcha'u Kaf Yachad HaRim Yiraneinu", let the rivers clap their hands, let the mountains sing for joy together I realized the mountains do sing! But what are they singing about? Why don't they sing alone? And what is their connection to the rivers?
Maybe we can offer as follows. Water comes from the skies in small drops. These drops fall on the mountain which channels them in small streams that turn into raging rivers whose rushing waters and roaring rapids sound like people clapping.
We know that Torah is compared to water. "Yaarof KaMatar Likchi" (Haazinu 32:2). Drops of Torah fall from Shamayim onto the mountain. The mountain is the Rebbi who responsible to put the torah together and pass it along to Am Yisroel. The mountain is merely a link in the chain from Shamayim. This why, although, "Hashem Moloch Gei'us Laveish", Hashem dresses in pride (Tehilim 93:1), the Torah is delivered through a low and humble mountain who recognizes that it is really Hashem's Torah and it plays only a middleman's role. That is why the Torah was given on the humble Har Sinai through the most humble person on the face of the earth, Moshe Rabbeinu.
The mountain does not boast of its individual accomplishment. Only when it hears the loud noises of Am Yisroel learning Torah way downstream, does it delight in knowing that its mission was accomplished and the sounds of Torah indeed fill the world. "Neharos Yimcha'u Kaf" when the rivers roar with the sounds of torah, then, Yachad HaRim Yiraneinu, together with them but in the background the humble mountains will rejoice.