Some hold that this phrase describes the present historical situation, particularly things concerning the church. They believe that in contrast with “the things which thou hast seen”—the vision of Christ (vs. 10-18)—“the things which are, and the things which shall be hereafter,” refer to actual historical events, presented symbolically.
Others hold that the clauses “the things which thou hast seen, and the things which are, and the things which shall be hereafter” simply refer to the things John had seen in vision, what he was seeing, and what he was still to see in the future (cf. v. 11).