Jim of www.biblebuslimericks.com wrote,
“In elementary school we learned that ROYGBIV, Red, Orange, Yellow, Green, Blue, Indigo, and Violet, were the seven colors of the rainbow. Together they make white light (the eighth) the color of the sun. See Christ, the Light of the world in all of this.”
This is an example of what we state at the top of this blog, “Join us as we search for sequences of ‘seven’ in the Bible, whether enumerated or not,” because the Holy Spirit did not always mention the number seven for us, but we have to look for non-enumerated sequences of seven, as Jim did here.
The first occurrence of the rainbow in the Bible was after the Flood,
“I set My rainbow in the cloud, and it shall be for the sign of the covenant between Me and the earth. It shall be, when I bring a cloud over the earth, that the rainbow shall be seen in the cloud; and I will remember My covenant which is between Me and you and every living creature of all flesh; the waters shall never again become a flood to destroy all flesh. The rainbow shall be in the cloud, and I will look on it to remember the everlasting covenant between God and every living creature of all flesh that is on the earth” (Genesis 9.13–16).
The Bible mentions the rainbow again in Ezekiel 1.28; Revelation 4.3; and Revelation 10.1.
Each of those times Ezekiel and John see a rainbow with God.
The reference in Revelation 4.3 says that the rainbow was like an emerald in appearance, so that it must not have had the seven colors that we associate with rainbows, but was a monochrome rainbow, which you can read about here: http://en.wikipedia.org/wiki/Rainbow