The device of the seven messages enables John to engage appropriately with seven different contexts in which his book would be read and also to integrate those contexts into the broader perspective of the rest of the book, in which John is concerned with the worldwide tyranny of Rome and, even more broadly, with the cosmic conflict of God and evil and the eschatological purpose of God for his whole creation. In this way he shows the Christians of each of the seven churches how the issues in their local context belong to, and must be understood in the light of, God's cosmic battle against evil and his eschatological purpose of establishing his kingdom.