The Catholic Encyclopedia lists 9 Scriptural events, commonly set forth by theologians, which shall lead up to the Last Judgment.
First Sign: General Preaching of the Christian Religion - Concerning this sign the Saviour says: "And this gospel of the kingdom, shall be preached in the whole world, for a testimony to all nations, and then shall the consummation come" (Matthew 24:14). This sign was understood by Chrysostom and Theophilus as referring to the destruction of Jerusalem, but, according to the majority of interpreters, Christ is here speaking of the end of the world.
Second Sign: Conversion of the Jews - According to the interpretation of the Fathers, the conversion of the Jews towards the end of the world is foretold by St. Paul in the Epistle to the Romans (11:25-26): "For I would not have you ignorant, brethren, of this mystery, . . . that blindness in part has happened in Israel, until the fullness of the Gentiles should come in. And so all Israel should be saved as it is written: "There shall come out of Sion, he that shall deliver, and shall turn away ungodliness from Jacob."
Third Sign: Return of Enoch and Elijah - The belief that these two men, who have never tasted death, are reserved for the last times to be precursors of the Second Advent was practically unanimous among the Fathers, which belief they base on several texts of Scripture. (Concerning Elijah see Malachi 4:5-6; Ecclesiasticus 48:10; Matthew 17:11; concerning Enoch see Ecclesiasticus 44:16.)
Fourth Sign: A Great Apostasy - As to this event St. Paul admonishes the Thessalonians (2 Thessalonians 2:3) that they must not be terrified, as if the day of the Lord were at hand, for there must first come a revolt. The Fathers and interpreters understand by this revolt a great reduction in the number of the faithful through the abandonment of the Christian religion by many nations. Some commentators cite as confirmatory of this belief the words of Christ: "But yet the Son of man, when He cometh, shall He find, think you, faith on earth?" (Luke 18:8).
Fifth Sign: The Reign of Antichrist - In 2 Thessalonians 2:3 sqq., St. Paul indicates as another sign of the day of the Lord, the revelation of the man of sin, the son of perdition. "The man of sin" here described is generally identified with the Antichrist who, says St. John (1 John 2:18), is to come in the last days. Although much obscurity and difference of opinion prevails on this subject, it is generally admitted from the foregoing and other texts that before the Second Coming there will arise a powerful adversary of Christ, who will seduce the nations by his wonders, and persecute the Church.
Sixth Sign: Extraordinary Perturbations of Nature - The Scriptures clearly indicate that the judgment will be preceded by unwanted and terrifying disturbances of the physical universe (Matthew 24:29; Luke 21:25-26). The wars, pestilences, famines, and earthquakes foretold in Matthew 24:6 et seq., are also understood by some writers as among the calamities of the last times.
Seventh Sign: The Universal Conflagration - In the Apostolic writings we are told that the end of the world will be brought about through a general conflagration, which, however, will not annihilate the present creation, but will change its form and appearance (2 Peter 3:10-13; cf. 1 Thessalonians 5:2; Apocalypse 3:3, and 16:15). Natural science shows the possibility of such a catastrophe being produced in the ordinary course of events, but theologians generally tend to believe that its origin will be entirely miraculous.
Eighth Sign: The Trumpet of Resurrection - Several texts in the New Testament make mention of a voice or trumpet which will awaken the dead to resurrection (1 Corinthians 15:52; 1 Thessalonians 4:15; John 5:28). According to St. Thomas (Supplement 86:2) there is reference in these passages either to the voice or to the apparition of Christ, which will cause the resurrection of the dead.
Ninth Sign: The Sign of the Son of Man Appearing in the Heavens - In Matthew 24:30, this is indicated as the sign immediately preceding the appearance of Christ to judge the world. By this sign the Fathers of the Church generally understand the appearance in the sky of the Cross on which the Saviour died or else of a wonderful cross of light.
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From the Catechism of the Catholic Church...
The Church's ultimate trial
675 Before Christ's second coming the Church must pass through a final trial that will shake the faith of many believers.574 The persecution that accompanies her pilgrimage on earth575 will unveil the "mystery of iniquity" in the form of a religious deception offering men an apparent solution to their problems at the price of apostasy from the truth. The supreme religious deception is that of the Antichrist, a pseudo-messianism by which man glorifies himself in place of God and of his Messiah come in the flesh.576
676 The Antichrist's deception already begins to take shape in the world every time the claim is made to realize within history that messianic hope which can only be realized beyond history through the eschatological judgment. The Church has rejected even modified forms of this falsification of the kingdom to come under the name of millenarianism,577 especially the "intrinsically perverse" political form of a secular messianism.578
677 The Church will enter the glory of the kingdom only through this final Passover, when she will follow her Lord in His death and Resurrection.579 The kingdom will be fulfilled, then, not by a historic triumph of the Church through a progressive ascendancy, but only by God's victory over the final unleashing of evil, which will cause His Bride to come down from Heaven.580 God's triumph over the revolt of evil will take the form of the Last Judgment after the final cosmic upheaval of this passing world.581
574 Cf. Luke 18:8; Mt 24:12.575 Cf. Luke 21:12; Jn 15:19-20.576 Cf. 2 Thessalonians 2:4-12; 1 Thessalonians 5:2-3; 2 John 7; 1 John 2:18,22.577 Cf. DS 3839. 578 Pius XI, Divini Redemptoris, condemning the "false mysticism" of this "counterfeit of the redemption of the lowly"; cf. GS 20-21.579 Cf. Revelation 19:1-9.580 Cf Revelation 13:8; 20:7-10; 21:2-4.581 Cf. Revelation 20:12 2 Peter 3:12-13.
http://www.vatican.va/archive/ccc_css/archive/catechism/p1s2c2a7.htm
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From the Catechism of the Catholic Church...
The Church's ultimate trial
675 Before Christ's second coming the Church must pass through a final trial that will shake the faith of many believers.574 The persecution that accompanies her pilgrimage on earth575 will unveil the "mystery of iniquity" in the form of a religious deception offering men an apparent solution to their problems at the price of apostasy from the truth. The supreme religious deception is that of the Antichrist, a pseudo-messianism by which man glorifies himself in place of God and of his Messiah come in the flesh.576
676 The Antichrist's deception already begins to take shape in the world every time the claim is made to realize within history that messianic hope which can only be realized beyond history through the eschatological judgment. The Church has rejected even modified forms of this falsification of the kingdom to come under the name of millenarianism,577 especially the "intrinsically perverse" political form of a secular messianism.578
677 The Church will enter the glory of the kingdom only through this final Passover, when she will follow her Lord in His death and Resurrection.579 The kingdom will be fulfilled, then, not by a historic triumph of the Church through a progressive ascendancy, but only by God's victory over the final unleashing of evil, which will cause His Bride to come down from Heaven.580 God's triumph over the revolt of evil will take the form of the Last Judgment after the final cosmic upheaval of this passing world.581
574 Cf. Luke 18:8; Mt 24:12.575 Cf. Luke 21:12; Jn 15:19-20.576 Cf. 2 Thessalonians 2:4-12; 1 Thessalonians 5:2-3; 2 John 7; 1 John 2:18,22.577 Cf. DS 3839. 578 Pius XI, Divini Redemptoris, condemning the "false mysticism" of this "counterfeit of the redemption of the lowly"; cf. GS 20-21.579 Cf. Revelation 19:1-9.580 Cf Revelation 13:8; 20:7-10; 21:2-4.581 Cf. Revelation 20:12 2 Peter 3:12-13.
http://www.vatican.va/archive/ccc_css/archive/catechism/p1s2c2a7.htm
