Before printing presses were available, well-to-do people often “published” works especially in public readings, perhaps most often at banquets. But that the book of Revelation was read in churches alongside Old Testament Scripture suggests that the early Christians began treating it as Scripture then or soon afterward (d. also 22: 18-19).
That one person would read the work (“blessed is the one who reads”) and the whole congregation would hear it (“blessed are those who hear it”) fits what we know of the time; even in urban areas, many people could not read much.
“Blessed are” is the familiar ancient literary form “beatitude,” which is especially prominent in the Hebrew Bible and Jewish texts (e.g., Ps. 1:1; Prov. 8:34).13 The “blessing” form itself is general, but the context specifies the blessings of the end (Rev. 21-22) for which only the listener will be prepared (“the time is near,” 1 :3).
In biblical idiom, “hearing” also often meant “heeding,” i.e., obedience (e.g., the Hebrew of Gen. 26:5; 27:8), but John allows no ambiguity, adding “take to heart” (lit., “keep”); one used this language for observing commandments. Though Revelation is not a collection of laws, its message provides us demands no less serious (Rev. 12:17; 14:12; 22:7).
(Adapted from The NIV Application Commentary: Revelation, published by Zondervan. Buy the book here.)