What does Revelation 18:1 mean?

After an angel had explained the meaning of the ten horns and the waters to the apostle John (Revelation 17:12–18), another angel descended from heaven. John notes that this angel has great authority and a glory that brightens the earth. Given these accolades, some Bible teachers identify this angel as Christ. They point out that the word translated "angel" has always literally meant "messenger," and certainly Christ is God's perfect messenger. He also has great authority and glory.

When He commissioned His disciples, Jesus said, "All authority in heaven and on earth has been given to me" (Matthew 28:18). John and Peter, who saw Jesus transfigured on a mountain, wrote about His glory (John 1:14; 2 Peter 1:16–17). Nevertheless, the Bible occasionally presents angels as having authority and glory (see Matthew 1:20–21; Luke 2:8–9).

Since Revelation doesn't give much detail on this particular being, it's best not to be dogmatic. Whatever the exact identity is, what we're meant to do is focus on the message being delivered.