What John the Revelator Knew
"Revelation was written by an old man whose life was just about over. He was in exile, utterly desperate and dependent, and yet full of hope in a sovereign God because he knew that whoever sat on the throne in Rome did not finally decide what would happen in the world. He knew that there was a God who sat in heaven who would bring all of his promises to fulfillment. John could sit on Patmos full of hope, because he knew what this God was like.
This kind of biblical theology is practical. It makes a difference. God's promise to fill the earth with the knowledge of its Creator would be kept in his new creation. The God of the Bible makes promises, and the God of the Bible sovereignly keeps them.
Do you see the importance of this? As Christians, we need to know that God will continue to care for us, and that his continuing care is based not on our faithfulness but on his. It may be exciting for a little while to run around pretending that the world is some great spiritual laser-tag contest between the forces of darkness and the forces of light. And certainly there are very real evil forces that we as Christians come up against in the world and in our own hearts. But the outcome does not hang in the balance. Our God is a sovereign God. John the Revelator had hope not because he knew what he would do but because he knew what God would do."
Mark Dever, 9 Marks of a Healthy Church, pp. 79