Notwithstanding, not even then will the merciful and benignant God leave the race of men without all comfort; but He will shorten even those days and the period of three years and a half, and He will curtail those times on account of the remnant of those who hide themselves in the mountains and caves, that the phalanx of all those saints fail not utterly. But these days shall run their course rapidly; and the kingdom of the deceiver and Antichrist shall be speedily removed. And then, in fine, in the glance of an eye shall the fashion of this world pass away, and the power of men shall be brought to nought, and all these visible things shall be destroyed.
Source: The End of the World (Pseudonymous) (New Advent)