Noach: The Power of Repentance
A Patient G-d
Following the story line of our Parsha one discovers that G-d gave ample warning of the coming flood to the people of that generation. Noach was told to build his ark and collect his animals, for 120 years! The entire time he exhorted the people, pleaded, begged and cajoled, but they refused to take him seriously.
When the 120 years finally passed we are told that G-d reconsidered and gave them an additional seven days, hoping that they might repent during this time. When the seven days had passed G-d finally relented and let the rain fall. But did he let it pour down in drastic torrents immediately? No, far from it! First he let the rain fall in drizzle, just a pleasant sprinkle that was pleasing to the touch. He hoped that at least one person would take its lesson to heart and repent.
He then gradually ratcheted up the storm till it reached the tempestuous levels of deluge.
It was not till the last moment that G-d finally let the punishment come having assured himself that no one was denied an opportunity to repent.
Teshuva
This leaves us to marvel at the power of Teshuva. Even if one waits till the very last moment and even if the repentance is clearly inspired by fear of retribution (instead of a sincere yearning for G-d) it is accepted in Heaven and has the power to change the Divine decree.