Rev 2. The 7 churches reflect the varying conditions of the Church throughout the earth and throughout the NT age. It is a clear indication that the kingdoms of the world are still in the hands of Satan, although God continues to protect His Church through the agency of angels.
Rev 4.1 After this I looked, and there before me was a door standing open in heaven. And the voice I had first heard speaking to me like a trumpet said, “Come up here, and I will show you what must take place after this.” 2 At once I was in the Spirit, and there before me was a throne in heaven with someone sitting on it. 3 And the one who sat there had the appearance of jasper and ruby. A rainbow that shone like an emerald encircled the throne. 4 Surrounding the throne were twenty-four other thrones, and seated on them were twenty-four elders. They were dressed in white and had crowns of gold on their heads. 5 From the throne came flashes of lightning, rumblings and peals of thunder. In front of the throne, seven lamps were blazing. These are the seven spirits of God. 6 Also in front of the throne there was what looked like a sea of glass, clear as crystal.
This picture in heaven reflects God's intention to bring His Kingdom down to earth eventually. The rainbow indicates God's covenant with the earth, to protect it until the fires of judgment. The 24 elders are likely angels who protect God's promise of protection for both Israel (12 tribes) and the International Church (12 apostles sent to the nations).
Rev 4.6 In the center, around the throne, were four living creatures, and they were covered with eyes, in front and in back. 7 The first living creature was like a lion, the second was like an ox, the third had a face like a man, the fourth was like a flying eagle. 8 Each of the four living creatures had six wings and was covered with eyes all around, even under its wings. Day and night they never stop saying:
“‘Holy, holy, holy is the Lord God Almighty,’ who was, and is, and is to come.”
The 4 creatures were also angels, I believe, appearing as the cherubim in Ezekiel. They represent God's judgment against the earth, symbolized by creatures of great violence or power. A lion is predatory and powerful. The ox is very strong. The man is intelligent. And the eagle is an omnicient predator. There is no escape from these angels of judgment, who are intent upon protecting the holiness of God upon the earth.
Rev 5.1 Then I saw in the right hand of him who sat on the throne a scroll with writing on both sides and sealed with seven seals. 2 And I saw a mighty angel proclaiming in a loud voice, “Who is worthy to break the seals and open the scroll?
Christ's redemptive work allows God's work upon the earth, through the angels, which will prepare the earth for the saints' inheritance.
Rev 6.1 I watched as the Lamb opened the first of the seven seals. Then I heard one of the four living creatures say in a voice like thunder, “Come!” 2 I looked, and there before me was a white horse! Its rider held a bow, and he was given a crown, and he rode out as a conqueror bent on conquest.
The 4 horsemen represent these angelic judgments upon the earth, which have been taking place throughout NT history since the death of Christ. They are limited judgments leading to Armageddon. The white horse conquers kingdoms that pretend to establish a permanent kingdom on earth, in place of Christ's Kingdom.
3 When the Lamb opened the second seal, I heard the second living creature say, “Come!” 4 Then another horse came out, a fiery red one. Its rider was given power to take peace from the earth and to make people kill each other. To him was given a large sword.
This horseman doesn't allow the world to unite as in the Tower of Babel. Men try to do good without Christ, but their labor is cursed just as Adam in his sin had his labor cursed.
5 When the Lamb opened the third seal, I heard the third living creature say, “Come!” I looked, and there before me was a black horse! Its rider was holding a pair of scales in his hand. 6 Then I heard what sounded like a voice among the four living creatures, saying, “Two pounds of wheat for a day’s wages, and six pounds of barley for a day’s wages, and do not damage the oil and the wine!”
This horseman also frustrates the labor of Man, they're being unable to produce their own sustenance apart from God.
7 When the Lamb opened the fourth seal, I heard the voice of the fourth living creature say, “Come!” 8 I looked, and there before me was a pale horse! Its rider was named Death, and Hades was following close behind him. They were given power over a fourth of the earth to kill by sword, famine and plague, and by the wild beasts of the earth.
This horseman brings about death as the ultimate curse of sin. Note how it is only a fourth of the earth, and not yet world-wide judgment. History is filled with examples of divine judgment against nations, and yet without completely destroying them.
9 When he opened the fifth seal, I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained.
Sadly, when the world is under judgment, the saints suffer from those who are bringing this divine judgment upon the world.
Rev 6.12 I watched as he opened the sixth seal. There was a great earthquake. The sun turned black like sackcloth made of goat hair, the whole moon turned blood red, 13 and the stars in the sky fell to earth, as figs drop from a fig tree when shaken by a strong wind. 14 The heavens receded like a scroll being rolled up, and every mountain and island was removed from its place.
...They called to the mountains and the rocks, “Fall on us and hide us from the face of him who sits on the throne and from the wrath of the Lamb!
The 6th seal reveals the world's recognition of their ultimate failure. It is a prolepsis of Christ's Coming, which will bring the Kingdom of God down upon the earth at Armageddon.