The Gemara (Chagigah 12a) tells us that when Hashem created the world, it kept expanding, like two balls of yarn that keep unraveling and do not stop, until Hashem made it stand still. Similarly, when He created the waters, they also kept expanding until Hashem stopped them, and they dried up. We see this from one of the Names of Hashem, א-ל ש-די (Bereishis 35:11), which means that Hashem is the One: שאמרתי לעולם די - Who said to the world: Enough!”
Why does the Gemara find a need to elaborate on the way the universe would have kept expanding if not for Hashem demanding that it stop?
According to the Kli Yakar (pasuk 6), Chazal are attempting to explain the source of man’s resistance to restriction and limitation. Left alone, there would be no end to his quest for pleasure and to the fulfillment of his desires. Yet where does this nature come from?
The Kli Yakar explains that it comes from the sources of our components. Man has a soul, which comes from Heaven, and a body, which is composed of earth mixed with water. (See Rashi Bereishis 2:6.) From these three – ארץ, י ,םשמים - comes man, איש. As such, he has characteristics of these three elements. Just as children are usually born with a nature similar to their parents, man has the nature of his elemental parents. Since we derive from eretz, yam, and shamayim, our nature and character are no different from those entities themselves.
Left to their own devices, the earth, water, and skies would have kept expanding, just like balls of yarn unravel without end. That is their nature: unrestrained and ungoverned, given to no limitation. So, too, man would also like to expand and fulfill his desires, with no restrictions. However, as we see from the aforementioned Gemara, the universe, and also the sea, heeded Hashem’s call to stop and were made compliant by Hashem.
This, says the Kli Yakar, is the reason the Gemara tells us what took place when Hashem created the world. There is a lesson here for us all. A person may not say that he cannot stop running after his desires, since the will to do so is in his makeup. Rather, he should look to the source of his elemental DNA and realize that he can stop, he can listen to the rules. Just as the eretz, yam, and shamayim were able to change their nature when commanded by Hashem — and did not go an inch farther — we can also subordinate our nature and follow the mitzvos. This is also the meaning of the Medrash (Yalkut Shimoni 942), which tells us that we should look at the shamayim, the eretz, and the yam, and see if they changed their middos, their behaviors. Just as the sky and earth and sea have not deviated from Hashem’s command throughout history, we, as their constitutional progeny, can also live lives where we do not deviate from His command.
This also gives new meaning to the Gemara (Sotah 17a), which describes how the techeiles [blue string] in the tzitzis serves as an aid to remember and keep all the mitzvos. The blue string is there to make us think of the sea,
