As I looked at this rainbow of color, I’m reminded that God will never flood the earth again and judge the entirety of humanity (except for those 8). That’s exactly what He told Noah He would never do. But to us, that seems like the simple explanation. I wonder when Noah saw that first rainbow, he knew exactly what it meant. I think he did in my opinion.

“In the six hundredth year of the life of Noah, in the second month, on the twenty-seventh day of the month, on this day all the fountains of the abyss were broken up, and the flood gates of heaven were opened.” Genesis 7:11
Genesis 7:11 tells us that the fountains or natural springs burst forth from the abyss or bottomless pit from the ground and the flood gates or windows/torrents of heaven opened up from the firmament and poured water out. It was two fold. From above and from below. Noah saw this promise, looking to the heavens toward the firmament and following the colors all the way down to the ground. From the heavens above to the ground below.
Not only that, but when reading Genesis 9:13-14, God tells Noah that seeing this rainbow coming from the clouds is a reminder of this covenant. “I set My rainbow in the cloud, and it shall be a sign of the covenant between Me and the earth. And it shall be when I gather clouds upon the earth, that My rainbow shall be seen in the cloud.” And we should be reminded of our covenant with God through Jesus Christ and His promise to come back a second time to have His final judgement. I’ll get to that in a second.

We also see the rainbow of God in the throne room in Revelation 4. “Immediately I was in the Spirit; and behold, a throne was set in heaven (and One sitting on the throne) similar in appearance to a jasper and sardius stone, and there was a rainbow around the throne, in appearance like an emerald.” Revelation 4:2-3
This promise by God is also pointing to the new covenant with Jesus who will come in the clouds to judge once again. But this time is different, He’s judging by fire. “Jesus said to him, “You said it. Nevertheless, I say to you, from now on, you will see the Son of Man sitting at the right hand of the Power, and coming on the clouds of heaven.” Then the high priest tore his clothes, saying, “He has blasphemed! What further need do we have of witnesses? Look, now you have heard His blasphemy!” Matthew 26:64-65
The Sanhedrin cried blasphemy over this claim. They knew what Jesus meant by this “coming in clouds” and God’s promise of not destroying the earth again by water. He was claiming to be God who made the covenant with Noah and his generations. And what did the Sanhedrin do in modern times? They made the Noahide Laws for the Gentiles (goyim) and made their symbol, you guessed it, a rainbow. Do you see the mockery of Jesus here?

But check this out in Matthew 24:30, “And then shall appear the sign of the Son of Man in heaven, and then all the tribes of the earth shall mourn, and they shall see the Son of Man coming on the clouds of heaven with power and great glory.” What is the sign? No one actually knows. Constantine said he saw a Cross in the heavens and that this was a sign to change his ways and covert the Roman Empire to Christianity as a whole. I don’t buy it. This was the birth of the false universal church called Roman Catholicism.
Scholars have no idea what this sign actually is and everything at this point is conjecture and a theory. I’ll go out on a limb and say that this sign is the sign of the covenant with Noah of a rainbow protruding from the throne room of God, as we see in Revelation with the One sitting on the throne. It’s a reminder of the first judgement of Creation that the second and final judgement on Creation is about to happen.
My last thought on the rainbow is what we see today. I think the most ironic thing about this rainbow covenant because of the deluge is what is happening today. A certain group of people have taken this symbol knowing full well what it means and have used it for their own propaganda to not only mock the covenant of God, but to confuse those who are already confused. He shows them to literally mock themselves. Satan saw the destruction of humanity and still pushes his own covenant with these earth dwellers through their rainbow which is bringing judgement upon their heads. The first judgement came by water and a world wide flood. The second judgement comes by fire that sends them to the LAKE of fire. God is merciful and righteous.

“And the Lord God said to Noah, “This is the sign of the covenant which I make between Me and you, and between every living creature which is with you for all generations: ~~> I set My rainbow in the cloud, and it shall be a sign of the covenant between Me and the earth. And it shall be when I gather clouds upon the earth, that My rainbow shall be seen in the cloud. <~~ And I shall remember My covenant, which is between Me and you, and between every living soul in all flesh, and there shall no longer be water for a deluge, so as to blot out all flesh. And My rainbow shall be in the cloud, and I will look at it and remember the everlasting covenant between Me and the earth, and between every living soul in all flesh, which is upon the earth.” Genesis 9:12-16