Gregory Beale examined the Old Testament background of John’s claim that “this is the last hour,” tracing it mostly back to Daniel 8-12, the only place where he could locate a combination of “last” and “hour.” He claimed that John was talking about the eschatological trial that was inaugurated in his day, but one that continued through the whole church age.

It seems better to me to see it as the eschatological trial of the first century. John is (as Beale recognised) drawing on the Olivet Discourse, but there the coming of false Christs and false prophets is a sign of the end of the age, and of the destruction of the temple. The tribulation that Jesus talks about is the tribulation of the birth pangs of the new covenant. John is talking about the same event, only telling his readers that the timetable is almost completed.

Peter J. Leithart, 1 John: Last Hour, www.leithart.com