In Parshas Bereishis, man begins by mixing good and evil in Gan Eden. By Parshas Noah, he has already sunk so low that the entire earth is no longer mixed, but almost entirely evil aside from Noah himself. What is evil? What does it mean to do evil?
Morality consists of boundaries, areas where we may go and where we may not good. Good is defined by staying within Godly boundaries. Evil is defined by crossing those boundaries and destroying them. Chaos and order. Good and evil. The Godly and the ungodly. These are the parameters of creation.
When God created the universe ex-nihilo, order was formed out of chaos through a series of divisions. When mankind sank into hopeless and irredeemable evil, those boundaries began to fray, and were finally collapsed completely.
Each boundary had been erected for the purpose of man and life on earth.
First the light was divided into day and night. Then the sky was divided into atmosphere and ocean. And then the ocean itself was divided to make room for dry land, where man and animals could live. The stars were created to govern the seasons and the passage of time. With the flood each of those boundaries was removed. Night and day ceased to function. The heavens poured down on the earth. The dry land was swallowed by the ocean. Seasons ceased to be.
As man tore down Godly boundaries, so too God tore down the boundaries he had erected for the benefit of man. And only the Godly boundaries that Noah and his family kept on the Ark saved them from becoming destroyed along with all other life. Only by keeping the Godly boundaries does humanity enable the maintenance a world where dry land is not flooded by the ocean, where the sky and ocean are divided, and night and day, and the seasons make life livable.
Just as the Sabbath is a boundary for the human week, so too does every commandment serve as a boundary for our thoughts and our actions. The commandments represent the way of God, and they are no different than the commandments imposed on the sea and the sky, the stars and all the world around. But the only difference is in us, that we can choose to keep them or not, and thereby face the consequences.