The Tribulation is the time of the outpouring
of the wrath of God upon a wicked world.

At the time of the horsemen, when the fourth
horsemen rides forth, the word says, ". . .And
power was given unto them over the fourth
part of the earth, to kill with sword, and with
hunger, and with death, and with the beasts
of the earth" Revelation 6:8

In the beginning days of the Revelation,
about twenty-five per cent of the world is
killed in the opening wars and pestilences of
those days.