When John enters heaven (Revelation 4), He sees the Enthronement as a precious stone, a stone glowing with light, a stone that sparkles like a star, and He is surrounded with a rainbow that is also described as a precious stone.
Specifically, the stone is the emerald. This is the fourth stone in the list of the stones on the high priest’s breastplate, the first in the second row (Exodus 28:18). Judah has taken the first spot, and the next three sons move down a notch. Judah used to be in the fourth position, but now the thirdborn, Levi, has moved to the fourth position.
The emerald is a Levite stone, and the rainbow around the throne of God is like an emerald. Levi is the tribe that sparkles green with new life. That makes the rainbow a priestly rainbow, and probably is to be understood as the 24 elders.
They are around the throne as a rainbow. What does it mean to say that there’s a rainbow around the Lord’s throne? The rainbow, of course, goes back to the flood. There are a couple of things to notice about the rainbow in the flood narrative (Genesis 9:13-16).
First, terminology: There is no separate Hebrew word for “rainbow.” The word is simply “bow,” which refers to a weapon, a bow that goes with arrows. This is what the word means in most of its uses in the OT. Yahweh has a bow in this sense (Psalm 7:12), with which He makes war against His enemies. This means that when Yahweh puts His bow in the sky, He is hanging up His weapon of war against the wicked. A bow in the sky means peace, means that Yahweh is not going to make war anymore.
According to Genesis 9, the bow in the sky is a reminder to Yahweh of His promise. It is not first of all a memorial for human beings, but a memorial before Yahweh so that He remembers what He said to Noah. The bow appears in the cloud, the cloud that will later be a sign of Yahweh’s presence with His people, and when it appears He will remember His covenant promise that He will not again destroy the world as He had done in the flood.
At creation, Yahweh put signs in the heavens sun, moon, stars. After the flood, as the world is created again, another sign (Genesis 9:13) appears in the heavens, the rainbow in the cloud, a trick of light that links with the ruling lights of the firmament.
Scientifically, we know that the bow forms in the sky as a result of sunlight refracting through the raindrops that make up the clouds. Since God radiates light, and travels in a cloud, He must be surrounded by a rainbow wherever He goes in His cloud-chariot.
The only other place in the OT where the bow refers to the rainbow specifically is in Ezekiel, and there Ezekiel describes the “radiance” that surrounds the throne as being like “the appearance of the rainbow in the clouds on a rainy day” (1:28). The radiance is a fire that looks like “amber” and is also described as being like the appearance of a bow. Whether the appearance refers to the color or to the shape is immaterial.
The radiance-bow is “round about” the throne. Ezekiel 1:28 is clearly alluding to the original rainbow passage in Genesis 9. There, Yahweh promised to remember His promise when He saw the “bow . . . in the cloud.” Ezekiel sees the appearance of a bow which is in the cloud on a day of rain.
These are the only two places in the OT where “bow” and “cloud” occur together. So it makes sense to interpret what Ezekiel sees in the light of Genesis 9. Yahweh said that He would remember His promise when He saw the bow in the cloud, and Ezekiel says that the radiance from the throne and the One on the throne is like a bow in a cloud on a rainy day, a radiance that is “round about.”
The Lord, in other words is constantly surrounded by this memorial. He never forgets His promise.
Revelation adds to this by describing the rainbow as a Levitical emerald. The Levitical tribe is a kind of human rainbow. As mediating priests, the Levites are a continuous human reminder of the Lord’s promises. Levites also stand between Israel and the Lord, to absorb the wrath of God that breaks out against the wicked, as Aaron stops a plague with his censor (Numbers 16:41-50). Aaron makes a cloud with the incense, and stands in his rainbow-colored clothing in the midst of the cloud and stops the plague.
The priesthood was a human rainbow, and now that human rainbow is the new covenant priesthood of the church. We are emerald lens, the green-tinted visor, surrounding God’s throne, through which He views the rest of the world. As we gather around the throne, we ourselves become the precious stones that are the memorials of God’s promise, reminders to Him to keep covenant.