When Hashem opened the floodgates so that, “all the fountains of the great deep broken up, and the windows of heaven were opened,” it was almost a passive act – the waters were not driven together, they were merely released to go where they wanted. The waters above wanted to come down, and the waters of the deep wished to flow upward. The Flood was an act of unification.
But G-d had originally split the waters between those of the deep, and those of heavens, an act of separation that He had commanded on the second day. The act of the flood was in fact a partial unmaking of the initial act of creation. Once the restraints were lifted, what did the waters want to do? Merge once again. We know that without the separation put in place by Hashem, all of these dualisms want to flow together again, to become one. And when Hashem unifies the things that He separated, it is a destructive act. The Flood unmade the fundamental separation that allows life to exist on this earth.
Waters from below and above want to unite – midrashim point out that when tzaddikim like Moshe and Rivka and Yaakov came to wells, the water would rise up to meet them. The water understood that reunification of the waters above and below would come about through the acts of great people, and so when a tzadik came close, the waters would eagerly rise in anticipation.
Man’s job, in completing the creation of the world, is in fact to unify that which has been divided! We are meant to unify the dualisms in the world, and to do so in a holy manner: heaven and earth, man and woman, the waters above and the waters below (and countless others). Why, if Hashem merges that which is divided, it is destructive of life, while if we succeed in our mission, it is the ultimate act of holiness? If G-d merges heaven and earth, we cease to exist (as seen with the giving of the first two commandments). But if we succeed in merging heaven and earth, then we are fulfilling our destiny?!
One possible answer is to see that Hashem limited his own role. Just as the Torah was given in its entirety on Har Sinai (and we would not accept any prophet claiming to have a G-d-given addendum), G-d finished creating the world at the end of the sixth day – any more acts of creation on this earth are either biological ones (encouraged by the angels, and not by G-d directly), or creative acts committed by mankind ourselves.
In other words, the burden of completing G-d’s creation falls entirely on our shoulders. This is our mission in the world, and creative acts of unification are entirely within our remit. G-d yielded this role to us as part of his tzimtzum when he finished making the world. When mankind brings heaven and earth closer together, it is a beautiful, holy and creative act. But when Hashem does the same thing, it was at best a rinse cycle for the earth, allowing it to grow anew. At worst, it was an act of annihilation of countless lives.
Water itself, of course, is full of symbolism. Water itself is a prerequisite for life, but it is not life itself. All living things are made up of a majority of water (humans ranging from 55-78%). If we lack water, then we perish, but it has no spirit of its own. It is a building block for all creativity on this world. Physical water is an essential part of our bodies.
Water is often linked to Torah. The Torah itself is not alive; it is comprised of words on parchment. But we call it “the tree of life,” because it is our spiritual water; it is an essential part of our souls. The midrash tells us that if Torah was no longer being learned and practiced, then the world would cease to exist – it would have no reason to remain any longer, since we would no longer be working to complete our destiny, and the earth would cease to have any purpose. Learning Torah is also unifying a dualism: the physical water necessary for the life and health of our bodies, and the spiritual water of the Torah necessary for the life and health of our souls.