Light of the World
“God is light.” This concept stated by the Apostle in 1 John 1:5 is expressed numerous times throughout the Bible (Psalm 27:1, Psalm 76:4, John 1:9, John 8:12, etc.). This will reach its literal fulfillment when He establishes His Kingdom on earth. In Isaiah and in Revelation, it says that the Lord Himself will provide the light for His Kingdom:
The sun will no more be your light by day,
nor will the brightness of the moon shine on you,
for the Lord will be your everlasting light,
and your God will be your glory.
Your sun will never set again,
and your moon will wane no more;
the Lord will be your everlasting light,
and your days of sorrow will end. -Isaiah 60:19-20
There will be no more night. They will not need the light of a lamp or the light of the sun, for the Lord God will give them light. And they will reign for ever and ever. -Revelation 22:5
Wells of Salvation
It is also said that the living water comes from God (Isaiah 12:3, John 4:10-14, John 7:37-38, etc.). This also reaches its literal fulfillment in the Kingdom, as stated in Ezekiel 47 and Revelation 22:
Then the angel showed me the river of the water of life, as clear as crystal, flowing from the throne of God and of the Lamb down the middle of the great street of the city. -Revelation 22:1-2
Water and Light
As you are probably aware, water has three phases: solid, liquid, and gas. God is described in three different natures: Father, Son, and Spirit.
God is light and the living water flows from within Him. As you are also probably aware, when light hits water, the reflection, refraction, and dispersion of the light creates a rainbow. There are seven colors in a rainbow, and the Bible tells us that God has a 7-fold Spirit (Isaiah 11:2, Revelation 4:5, etc.): The Spirit of the Lord, the Spirit of wisdom and of understanding, the Spirit of counsel and of might, the Spirit of the knowledge and fear of the Lord.
And it just so happens that the radiance that surrounds God’s throne is described as a rainbow:
Above the vault over their heads was what looked like a throne of lapis lazuli, and high above on the throne was a figure like that of a man. […] Like the appearance of a rainbow in the clouds on a rainy day, so was the radiance around him. -Ezekiel 1:26-28
At once I was in the Spirit, and there before me was a throne in heaven with someone sitting on it. And the one who sat there had the appearance of jasperand ruby. A rainbow that shone like an emerald encircled the throne. -Revelation 4:2-3
So God reigns from His throne and is the source of the Kingdom’s light and of the living water. On God’s throne, light meets water and is surrounded by the radiance of a rainbow. God’s three natures and water’s three phases, God’s seven Spirits and light’s seven colors.