What will it be like when the world comes to an end?
When the world comes to an end, Christ comes for all to see.
The dramatic upheavals (Lk 18:8; Mt 24:3-14) that are foretold in Sacred Scripture the wickedness that will be plainly manifest, the trials and persecutions that will put the faith of many to the test these are only the dark side of the new reality: God's definitive victory over evil will be visible. God's glory, truth, and justice will stand out brilliantly. With Christ's coming there will be "a new heaven and a new earth". "He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning nor crying nor pain any more, for the former things have passed away" (Rev 21:4).
What will it be like when Christ judges us and the whole world?
Even Christ cannot help someone who does not want to know anything about love; such a person judges himself.
Because Jesus Christ is "the way, and the truth, and the life" (Jn 14:6), he will show what is of lasting value in God's sight and what is not. Held up to the standard of his life, the full truth about all people, things, thoughts, and events will come to light. (YOUCAT questions 111 & 112)
Dig Deeper: CCC section (675-682) and other references here.
Part 1: The Profession of Faith (26 - 1065)
Section 2: The Profession of the Christian Faith (185 - 1065)
Chapter 2: I Believe in Jesus Christ, the Only Son of God (422 - 682)
Article 7: "From thence He will come again to judge the living and the dead" (668 - 682)
I. HE WILL COME AGAIN IN GLORY ⇡
The Church's ultimate trial ⇡
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
574.
575.
Cf. Lk 21:12; Jn 15:19-20.
576.
Cf. 2 Thes 2:4-12; 1 Thes 5:2-3; 2 Jn 7; 1 Jn 2:18,22.
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
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.
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
579.
Cf. Rev 19:1-9.
580.
581.
Cf. Rev 20:12 2 Pet 3:12-13.
II. TO JUDGE THE LIVING AND THE DEAD ⇡
Following in the steps of the prophets and John the Baptist, Jesus announced the judgment of the Last Day in his preaching.582 Then will the conduct of each one and the secrets of hearts be brought to light.583 Then will the culpable unbelief that counted the offer of God's grace as nothing be condemned.584 Our attitude to our neighbor will disclose acceptance or refusal of grace and divine love.585 On the Last Day Jesus will say: "Truly I say to you, as you did it to one of the least of these my brethren, you did it to me."586
582.
Cf. Dan 7:10; Joel 3-4; Mal 3:19; Mt 3:7-12.
583.
Cf Mk 12:38-40; Lk 12:1-3; Jn 3:20-21; Rom 2:16; 1 Cor 4:5.
584.
585.
Cf. Mt 5:22; 7:1-5.
586.
Christ is Lord of eternal life. Full right to pass definitive judgment on the works and hearts of men belongs to him as redeemer of the world. He "acquired" this right by his cross. The Father has given "all judgment to the Son".587 Yet the Son did not come to judge, but to save and to give the life he has in himself.588 By rejecting grace in this life, one already judges oneself, receives according to one's works, and can even condemn oneself for all eternity by rejecting the Spirit of love.589
587.
Jn 5:22; cf. 5:27; Mt 25:31; Acts 10:42; 17:31; 2 Tim 4:1.
588.
Cf. Lk 21:12; Jn 15:19-20.
589.
Cf. Jn 3:18; 12:48; Mt 12:32; 1 Cor 3:12-15; Heb 6:4-6; 10:26-31.
IN BRIEF ⇡
Christ the Lord already reigns through the Church, but all the things of this world are not yet subjected to him. The triumph of Christ's kingdom will not come about without one last assault by the powers of evil.
On Judgment Day at the end of the world, Christ will come in glory to achieve the definitive triumph of good over evil which, like the wheat and the tares, have grown up together in the course of history.
When he comes at the end of time to judge the living and the dead, the glorious Christ will reveal the secret disposition of hearts and will render to each man according to his works, and according to his acceptance or refusal of grace.