At once I was in the Spirit, and behold, a throne stood in heaven, with one seated on the throne.  And he who sat there had the appearance of jasper and carnelian, and around the throne was a rainbow that had the appearance of an emerald.  Around the throne were twenty-four thrones, and seated on the thrones were twenty-four elders, clothed in white garments, with golden crowns on their heads.  From the throne came flashes of lightning, and rumblings and peals of thunder, and before the throne were burning seven torches of fire, which are the seven spirits of God,  and before the throne there was as it were a sea of glass, like crystal.
By the time the apostle John wrote the book of Revelation, most of the other apostles had been martyred. In Revelation 2, Jesus tells the church of Smyrna that some of them would be thrown into prison and others would lose their lives. In Revelation 3, Jesus encourages the church of Philadelphia to not fear the synagogues that would persecute them. The people of God are afraid.
So in the vision revealed to John, what does he see? In verse 2, the first thing John sees in heaven is a throne and One seated on it. My wife and I are expecting our third child soon. We anticipate chaos. This world is often chaotic, but we can know that there is a King and He is on the throne.
This King created all things and is sovereign over all things. He is not just King inside the church or the spiritual parts of our lives. He is the King of everything that exists and He upholds the universe by the word of His power. He is sovereign over every molecule.
A Romanian pastor was jailed and beaten and he said this to his captors:
My God is teaching me a lesson. I do not know what it is. Maybe he wants to teach me several lessons. I only know, sirs, that you will do to me only what God wants you to do—and you will not go one inch further—because you are only an instrument of my God.
We may not always understand what God is doing, but we know that He is King and He can and He will ultimately work all things for our good. Our God will conquer the chaos.
In verse 6, John sees a sea of water so still and peaceful it looks like glass. In the Bible, the sea is usually a scene of chaos. Paul gets shipwrecked, Jonah gets swallowed by a fish, and the Egyptian army is drowned in the sea. Water is chaos, but Jesus comes on the scene calms the storm.
We serve a sovereign King. This does not mean we will avoid suffering, but we can rest assured that the waters will be stilled, that the King is seated on His throne.