In chapter 17 we see an illustration of some of the judgement from the previous chapter. It is illustrated by a prostitute (named Babylon). Babylon is a picture of the sin of the world. Babylon was a great kingdom that ruled over much of the world and destroyed Jerusalem. They took the holy items from the temple and desecrated them. We need to respect those things that God says are holy. Your life is holy so you must respect it.
We learn in this chapter that the leaders of the world are committing adultery with Babylon. Spiritual adultery is anything that take away from the worship of God. When you and I become addicted to something other than the worship of God, we enter into spiritual adultery. This could be materialism or money or anything that take you away from God.
Why adultery? We all are the bride of Christ. We are to be the wife of God and these things would be unfaithful to Him. Instead of being the bride of Christ, we go after the spirit of this world.
The text shows the leaders of the world being drunk with this prostitute. But the prostitute is not drunk on wine but on the souls of the people of God. We live in a wicked world.
After this we see a war between the Lamb of God and the beast. Whose side are you going to be on? We must choose sides. Choose carefully because we already know the ending. Jesus, the Lamb of God will win.