Whenever you see a rainbow?

Having just returned from a country that exists mostly under sea level, witnessing the unfolding drama in parts of England is incredible. Its hard to conceive of the scale of devastation being wrought by relentless rain and rising river levels. And then the knowledge that, in the midst of all that there is a shortage of clean water.
What is being demonstrated is how resourceful people can be, how upbeat amidst tragedy and loss. To see and hear folk being philosophical, retrieving what they can and moving what they can't and accepting their lot makes me wonder what I would do. How would I cope. Could I be so resigned. What are the important things and what would I want to save? Thank God for folk who are resilient in adversity. I hope the worst is over and that, as a nation we can learn how to avoid such catastrophe in the future - and be willing to pay not just for the clean up but for long term prevention.
What was that promise associated with the rainbow?