What is the significance of the Rainbow in the sky?

I researched books and found very few are written on the subject of God's Rainbow. However, it has great significance to mankind. The rainbow is placed in the sky by the Creator of both the universe and human beings.

One might say, What does the rainbow have to do with human behavior? My answer is, Everything. God reveals His very own personality in His rainbow. His desire is for us to get to know Him—to learn His characteristics and to become more like Him on this journey of life.

For Him to fulfill the purpose He has for each one of us, individually, He has given us a free will to make our own choices.