The real meaning and reason for the rainbow direct from the One who promised it, God. Part 1 of 2
Genesis 9:11-13 "Thus I establish My covenant with you: Never again shall all flesh be cut off by the waters of the flood; never again shall there be a flood to destroy the earth."
And God said, "This is the sign of the covenant which I make between Me and you, and every living creature that is with you, for perpetual generations:
"I set My rainbow in the cloud, and it shall be for the sign of the covenant between Me and the earth.