Revelation contains four series of seven messages or visions. These include letters to churches (chs. 2–3), seals on a scroll (4:1-8:1), trumpets (8:2-11:19), and bowls of wrath (chs. 15–16). There is a general movement from “the things that are” to “the things that are to take place after this.” Yet the visions sometimes return to subjects from the previous sections. The order in which John received the visions does not necessarily indicate the order of the events they symbolize.