When reading Parshat Noach, there are basic questions that arise. G-d has decided to destroy all flesh upon the earth, why is Noach then burdened with the task of transporting the animals to safety. Why is it his job in the first place?
Part of the answer requires asking why was Noach spared in the first place. We're not given any details what made Noach special except for his father Lemach's statement about Noach's name. He names him Noach, or Rest, saying; "He will comfort us from our work and the toil of our hands, which cometh from the ground which the LORD hath cursed."
It sounds as if this means that life is about to get easier for mankind but instead what happens is a great flood that destroys all life on earth. When the flood is done and Noach has returned to the earth and brings sacrifices to G-d, G-d states that he will not again curse the earth because of man and that all the seasons of life on nature Lo Yishbatu, Will Not Stop. Yishbatu comes from the same root as Shabbat, the day of rest and is a word that refers to resting. It seems that Lemach's hope for Noach only winds up being fulfilled after the flood itself, but rather than promising that man will be able to rest in working the earth, instead it is promised that the seasons will not rest because of man.
The first day of rest of the earth, the first Shabbat, occurred after G-d had completed the creation of the world. Everything in the world had come into being from the oceans and sky to the animal kingdom and finally man, the world was at last complete and G-d rested. Adam named every animal and was given stewardship of the garden of eden, to work and watch over it. But the rest did not last very long, Adam and Chava violated G-d's will and the completion of creation by listening to the serpent and eating from the tree and the earth was cursed for that.
Creation was no longer complete and the Shabbat was over. Work resumed and Adam was expelled from the garden of eden and into an incomplete creation in which he would have to toil on the earth. Following him were two sons, Kayin and Hevel (Cain and Abel) who took different paths. Hevel was a shepherd and Kayin worked the earth. Both Hevel and Kayin brought sacrifices to G-d of the work of their hands, yet G-d rejected Kayin's and accepted Hevel's. Why?
Sacrifice is primarily a means of showing gratitude to G-d by recognizing his supremacy in the natural order of the world. When a man brings a portion of his work to G-d, he is recognizing the G-d as the source of his productivity. Hevel brought from the best that he had to G-d while Kayin just picked out some of his produce and brought it over. While Hevel was accepting the supremacy of G-d, Kayin was essentially treating G-d as an equal or inferior even. Kayin did not recognize the supremacy of G-d in the natural order, instead he gave him what he had himself.
In doing so Kayin was repeating the sin of his parents who had eaten of the Tree of Knowledge in order to become equal to G-d, for which the earth that Adam and Kayin worked was cursed in the first place. Adam and Chava had subverted the natural order, listening to a member of the animal kingdom in a plot to subvert G-d's dominion. Hevel by contrast upheld the natural order by working as a shepherd.
The natural order begins with G-d, then man and then the animal kingdom. From greater to lesser. Before his sin, Adam had named the animals and thus defined their identities. After the sin Hevel took the proper road maintaining leadership over the animals while Kayin continued to 'Serve the Earth.' In the proper fulfillment of the natural order, G-d leads man who leads the animal kingdom. When the order is disrupted man sinks to his lower nature, takes counsel from his animal nature and even sinks down to the earth from which he came.
The great leaders of Israel were often shepherds. Avraham, Yitzchak and Yaakov maintained herds of sheep. By contrast the Egyptians worked the earth treating the Nile River which irrigated their crops as a deity. Moshe was a shepherd too and his treatment of the sheep in his charge demonstrated his fitness to lead Israel. Shaul, the first king of Israel, was a shepherd so was David. But Shaul demonstrated his unfitness to rule when instead of leading the people in the war on Amalek, he allowed himself to be led by them. As had happened to Adam, the inferior led the superior.
As the generations passed over the death of Hevel, instead of leading the animal kingdom, man went on to pervert the entire world down to the animal kingdom as well and thus G-d pledges to destroy the world, and specifically naming man and almost the entire animal kingdom, by types of creature. The world is flooded and rests as man and all life is cut off from the earth. The acts of creation that spread dry land across the surface of the waters and brought forth life are undone.
When the waters recede and Noach and the animals are released into a new world, a recreated world and Noach having become the first proper shepherd of life after the death of Hevel, is given new authority over the animal kingdom. All the animals of the world will now fear him and he and his descendants have the right to hunt and eat them. Having saved the animals, Noach has like Adam before him become a partner in the creation of the world's animal life.
Yet instead Noach turns to the earth again. Vayahel Noach Ish Haadama, And Noach the Man of the Earth Begins, we are told. What does he begin, after being cut off from the earth by water, he becomes a man of the earth again, plants a vineyard, gets drunk and is ridiculed by his son. The natural order of the world has been subverted again and in consequence the line of one of Noach's sons is cursed to become the slaves of slaves. And the descendant of that son, Nimrod, turns to founding the civilizations of Babylon and Assyria that will become the enemies of G-d and constructing a tower to make war on G-d, yet again an assault on the natural order.
The more man deviates from the natural order, the more corrupt the condition of the world becomes. Adam and Chava, Kayin and Noach all showed potential for upholding the order but wound up undermining it too. The first Shabbat could not endure because of that and when G-d states on recieving Noach's sacrifice that he will no longer curse the earth because of man, it is not properly a blessing but a recognition that man's heart contains evil from the beginning. Thus Noach relieves the curse on the earth not through his righteousness but because G-d recognized the futility of tying the nature of the world to man.
It is a mercy but one that hinges on the recognition of human weakness and potential for corruption. Man would no longer have to labor as hard on the earth, but not until Israel accepted the Torah and the Shabbat, the Day of Rest, in recognition of the original creation of man and the creation of the covenant of Israel with the Exodus, was there another piece of the earth that would have a similar close relationship with man at that, the Land of Israel, on which the eyes of G-d are set all year round and from which man is expelled when he defiles it. It is a land from which man was obligated to tithe the work of his hands as Kayin and Hevel had. It recreated the natural pre-noachide order of the world as it had been and as it had been meant to be and as it will be.