The Covenant of the Rainbow opened the way for repentance
The rainbow that G-d revealed to Noah after the Flood was not only symbolic of the Seven Noahide Commandments. It was also a turning point in the spiritual nature of the world.
The wicked people before the Flood did not have a capacity for repentance. Through the spiritually cleansing waters of the Flood, G-d made repentance available to all people from then on.
By repenting here in the physical world, we draw down from the spiritual realm a “rainbow” of G-dliness. It consists of three primary “colors” of Divine attributes (sefirot in Hebrew): Kindness, Judgment and Abounding Mercy.
This audio lesson is a synopsis of a chassidic discourse by the Lubavitcher Rebbe on this subject.
MP3 audio: https://asknoah.org/wp-content/uploads/covenant-of-the-rainbow.mp3