Dear  brethren,
We have now arrived at the last Sunday after Pentecost, the last Sunday of all the Liturgical Year. And because the Liturgical calendar follows, in a way, the cycle of all the history of Mankind, it is logical that the last Sunday of the ecclesiastical year should treat about the end of this world.
We have just heard the Gospel according to Saint Matthew in the chapter 24th  (vv. 15-35), quoting the words themselves of Our Lord, announcing the end of the world.
The end of the world, the last times, the apocalyptic times… these are some expressions, which could nowadays terrify some souls.
But the end of the world will be a reality; it will be a historical fact of the time to come.
It is even a dogma of Faith. Indeed, we profess this truth expressly in our Creed when we say: “I believe (that Jesus) shall come to judge the living and the dead” and “I believe in the resurrection of the dead”. Now, the glorious coming of our Lord and the resurrection of all the dead will be accomplished only after the end of this world.
So what should we think, according to our faith, about the end of this world?
For we Catholics the answer to this question must be find only from the teaching of our Holy Mother the Church. And the teaching of the Church about this matter can be summarised as follows: This world, in which we are living and just as God created it, will not exist forever. One day, this world will finish and it will be deeply transformed in a sort of a new creation.
From this statement logically two important questions arise in our minds concerning the end of the world: when and how this event will happen? To answer these questions two authorities are the unique sources about this matter: Sacred Scripture and Holy Tradition.

So, WHEN?
Both the Old and the New Testament speak about the end of the world. But, it is especially in the New Testament where we find the most clear and the most complete teachings about this truth.
The fact, for instance, that the first three Evangelists (the Synoptics) quote the discourse of Our Lord concerning the end of the world, shows the importance of this teaching in the doctrine of the Gospel.
Nevertheless, we find also many other references in the Epistles of Saint Paul and Saint John, and finally in the Apocalypse.
But, among all this texts, certainly the most explicit passage concerning the end of the world is to be found in the Gospel of St Matthew for the mass of today. Indeed, Saint Matthew in his 24th chapter quotes a very important discourse of Our Lord, pronounced towards the end of his public life. It is not always clear and easy to interpret it, because Jesus speaks indistinctly on two different events: the first one is the destruction of Jerusalem and the second one concerns the end of the World.
Our Lord speaks with exactness and precision about the destruction of Jerusalem (which did really happen in the year 70 A.D.), while He leaves in shadow the details about the end of the World. The reason is because His second (glorious) coming will be sudden and will surprise all men.
Now, concerning the exact date of this event, Jesus declares that, it was not allowed to Him to reveal in detail the time when the end of the world will come.
Saint Augustine explains masterly this matter, saying: “God intends to hide (the time of) the last day from us, so that our hearts may be always prepared for something which we know will come, although we do not know when… Even the Son of God made man says that He does not know the day, because it did not belong to His mission to teach it. It is not that the Father knows something, of which the Son is ignorant, since the knowledge and the wisdom of the Father are also His… He teaches as our Master but also keeps silent as a good teacher should do… It is a way of putting it, this, saying that the Son does not know those things which he does not teach. (In Enarr. in Ps. 36)
In consequence, all so-called prophecies concerning the precise date of the end of the world are pure speculations and the fruit of the imagination of false prophets. Let us be always prudent in this matter, because these so-called predictions attempt sometimes to introduce even among our faithful…
It is important to remember, once more, that neither Jesus-Christ, nor the Apostles, nor the Church ever revealed any precise date concerning the time of the end of the world.
In this sense, for example, the Church condemned the Millenarist theory (even in his mitigated form), which pretends that Jesus-Christ will come personally to govern the world one thousand years before the end of the world. This theory is absurd, as we will demonstrate in the next point.

Now, HOW?
Although the time of the end of this world is uncertain, we have, on the contrary, surer elements concerning the second aspect of this difficult matter: HOW?
How will it happen, how will the end of this world arrive?
Before answering this second question, it is necessary to give some precisions.
We can consider in the end of the world two distinct steps: the last times on the one hand, and the end itself of the world with the second coming of Jesus on the other hand This second step will precede the resurrection of the bodies and the last judgement.
Indeed, the end of the world or the destruction of the actual world will be preceded by a certain time (an era more or less long), during which some events will happen. These events will be varied and different. We call this period: the last times.
The teachings of Jesus Himself, of the Apostles and of the Fathers of the Church about this period of time are clearer than the exact date about the end of the world. They tech that there will be many particular and specific signs, which will precede the end of the world. But all these signs must be accomplished before arriving the end of the world itself.

Traditionally, we can summarise these signs in six points:
The first sign is the PREACHING OF THE GOSPEL in the whole world. Jesus Himself announces this sign when He says in the Gospel of today: “And the gospel of the kingdom shall be preached in the whole world, for a witness to all nations, and then will come the end” (Mt 24,14) Despite of the efforts of the Church in its missionary task since twenty centuries to announce the truth everywhere in the world, this sign is not yet accomplished,
The second sign concerns a GENERAL APOSTASY. Apostasy means a total rejection of the Faith. Indeed, a universal apostasy concerning the Faith will arrive in the last times, unique in its gravity and in its extension as never seen before in the History of the Church. Jesus Christ announced clearly this apostasy in two passages in the Gospels. The first one, in St Matthew (24,12): “And because iniquity will abound, the charity of the many will grow cold”. The other one, in St Luke (18,8): “When the Son of Man (that means Jesus Himselj) comes, will He find faith on the earth?”. Saint Paul in his second epistle to Thessalonians (2,3) is more explicit: “Let no one deceive you in any way, for the day of the Lord will not come unless the apostasy comes first, and the man of sin (that is, the Anti-Christ) is revealed, the son of perdition, who opposes and is exalted above all that is called God, or that is worshipped, so that he sits in the temple of God and gives himself as if he were God” We remark on this last text that this general apostasy (which means a betrayal to God) will reach in two aspects: the faith, by a denial of the foundations themselves of Revelation; and against the authentic worship by an attack upon the sacraments and especially the Holy Sacrifice of the Mass. One can speculate, whether the actual crisis of the Church concerning this general apostasy is signified by this sign… Despite the particular gravity of the actual crisis in the Church, it is nevertheless necessary that all the six signs of the last times will occur together; but all these signs have not yet come about.
The third sign concerns the general CONVERSION OF THE JEWS. In contrast with the second sign, the Apostasy, the conversion of the Jewish people will happen, announced by St Paul in the 11th chapter of the Epistle to the Romans. Saint Paul gives the reason for this conversion saying that it will be a proof of the infinite mercy of God, Who is always faithful to His promises. When will this conversion be realised and in what manner and proportion? It is a mystery, which Saint Paul does not give us the details…
The fourth sign is about the coming of the ANTICHRIST. Jesus Christ as well as St Paul and St John expressly speak about this mysterious “Antichrist”. What will be the exact nature of this Antichrist? The Fathers of the Church and the theologians dispute about that, because some of them consider him as an individual person, while others think that the Antichrist will be a group of persons or even a particular heresy. What is certain however, is the particularly dangerous and destructive character of the Antichrist, a unique force and the worst force of evil has ever existed.
The fifth sign will be manifested by the APARITION OF ELIAS AND ENOCH. Both the Old (Mal. 4,5-6) and the New Testament (Mt 17, 10-13; Heb 11,5) speak about these two great prophets, who never died, in order to be preserved to confront, to combat, the Antichrist, as explicitly mentioned in the Apocalypse in its eleventh chapter (v. 5).
The sixth and the last sign (and perhaps the most difficult to interpret), concerns MANY GENERAL AND EXTRAORDINARY CALAMITIES, which Jesus mentioned in the Gospels. These calamities are expressly cited by Jesus: wars, terrible diseases and famines, earthquakes and many cosmic phenomena, etc. It is important not to make any easy conjecture about these exceptional signs, as many false prophets do nowadays, because in all times of the history of the Church we can find these terrible signs.
We can conclude this difficult matter with a moral application to our lives, quoting again St Augustine. He compared the last day of this earth with our last day of our lives. Indeed, we are not sure to be alive to see to the last times of this world, while we are sure to die. In consequence, he exhorted us to live in fidelity to God, awaiting with peace the last time of our own life. Here is his commentary: “The last day will come, for our benefit, and we do not know when, so that living justly always, we shall not merely lose our fear of that day, but even we shall desire it; because just as it will increase the sufferings of the unfaithful, so it will put an end to the troubles of the faithful. You can now (in this life) choose one thing or the other, but when that day (the end of the world) comes, you will have no choice. Choose now! Because God in His mercy hides from you that which His same mercy had put off for a time “. (Idem) And elsewhere he adds: “We are not told the day or the hour (of our death) so that we will live in perpetual vigilance, because the eternal day will be the same as our last day on this earth. We can live like men or like sons of God The damned preferred to live like men, when they were called to live like sons of God; therefore they receive their sentence. You shall die like men. Live like sons of God and you will reign with God”.
Death is certain; therefore use it for your advantage, since it is a lesson of humility and the gate of Heaven. Only death is certain. All other evils are uncertain. A child has been conceived; but he may not be born; that is uncertain. Perhaps he will grow, perhaps not; perhaps he will reach old age, perhaps not; he may be rich, he may be poor, etc. … But, is it possible to say, perhaps he will die, perhaps not?… From the moment when a man is born, we must say the same thing. he will not be free from it (from death)… We will have afterwards what we have chosen here and reaped what we have sown.
Christ overcame the world (and death) by making Himself man and by dying for us. Let us, then, unite ourselves to our Victor, that we may win the victory with Him (for all eternity) “. (P.L. 38, 589-590)