Here Jacob is referring to the destruction of the wicked in the last days. The imagery of Babylon, the whore, and the great and abominable church are used to describe those who will be destroyed at this time. Revelation 18:2, 8 describes the destruction in a similar fashion, Babylon the great is fallen, is fallen, and is become the habitation of devils…Therefore shall her plagues come in one day, death, and mourning, and famine; and she shall be utterly burned with fire: for strong is the Lord God who judgeth her.