I love how this guy is so torn over what this might mean.
Wikipedia can help you figure that out:
A rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere.It's a beautiful display of God's handiwork.
Unfortunately, people tend to worship the created more often than the Creator.
And here's the auto-tuned song, which is almost as awesome as the original in its hilarity:
I love the internet!
(HT: Abraham Piper)