In his Commentaria in Ecclesiasticuм Blessed Rabanus Maurus Magnentius, Archbishop of Mainz and one of the most prominent teachers of the Carolingian age, called Praeceptor Germaniae, author of the hymn Veni Creator Spiritus, says that the false friends who "take thy seat" in Sirach 12:12 are to be understood as heretics, whose doctrine is full of errors and wickedness, crawling like a cancer (sideways). (mlat.uzh.ch (Patrologia Latina), Rabanus Maurus)

Apud Esaiam: Et erunt vobis hi omnes sermones sicut sermones libri qui signatus est: quem si dederis homini scienti litteras ad legendum, dicet: Non possum legere, Signatus est enim. (0682B) Sed in illa die audient surdi sermones libri ; et qui in tenebris et qui in nebula sunt, oculi caecorum videbunt (Isa. XXIX, 11, 18) .

Item apud Hieremiam: In novissimo dierum cognoscetis ea (Hier. XXIII, 20).

Item apud Danielem: Muni sermones et signa librum usque ad tempus consummationis, quoad discant multi, et impleatur agnitio ; quoniam cuм fiet dispersio, cognoscent omnia haec (Dan. XII, 4, 7) .

[11] And the vision of all shall be unto you as the words of a book that is sealed, which when they shall deliver to one that is learned, they shall say: Read this: and he shall answer: I cannot, for it is sealed.

Et erit vobis visio omnium sicut verba libri signati, quem cuм dederint scienti litteras, dicent : Lege istum : et respondebit : Non possum, signatus est enim.

[...]

[18] And in that day the deaf shall hear the words of the book, and out of darkness and obscurity the eyes of the blind shall see.

Et audient in die illa surdi verba libri, et de tenebris et caligine oculi caecorum videbunt.

[20] The wrath of the Lord shall not return till he execute it, and till he accomplish the thought of his heart: in the latter days you shall understand his counsel.

Non revertetur furor Domini, usque dum faciat et usque dum compleat cogitationem cordis sui : in novissimis diebus intelligetis consilium ejus.

[4] But thou, O Daniel, shut up the words, and seal the book, even to the time appointed: many shall pass over, and knowledge shall be manifold.

Tu autem Daniel, claude sermones, et signa librum usque ad tempus statutum : plurimi pertransibunt, et multiplex erit scientia.

[10] [...] none of the wicked shall understand, but the learned shall understand.

[...] neque intelligent omnes impii : porro docti intelligent.

Muni sermones et signa librum usque ad tempus consummationis, quoad discant multi, et impleatur agnitio ; quoniam cuм fiet dispersio, cognoscent omnia haec (Dan. XII, 4, 7) .

Guard the words and seal the book until the time of the consummation, until then many may learn and knowledge may increase; whereas when the scattering will happen, they will understand all these things.

By all means, I think these [prophetic developments] are better understood with regard to the Church, lest the Lord Jesus, with His second coming drawing near, seem to have foretold as being of great consequence [developments] that had been accustomed to happen to this world even before His first coming, and [lest] we be laughed at by those who have read in the history of nations more and much greater things than the ones at which we tremble as the final and most important of all. For the Church is the sun and the moon and the stars, to which it was said, “fair as the moon, bright as the sun” (Canticle of Canticles 6:9). In this world our Joseph [=son of Jacob and Rachel] is worshipped [=venerated] by the [moon], as though in Egypt [when he had been] lifted up on high from the lowliest [condition]. For the Joseph’s mother, who died before Jacob had come to his son, was certainly unable to worship him, in order that the truth of the prophetic dream (Genesis 37:9), to be fulfilled with Christ the Lord, might be preserved. For when “the sun shall be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of heaven shall be moved,” just as this passage was recorded by the other two Evangelists (Matthew 24:29, Mark 13:24), the Church will not be perceptible at that time, with the ungodly persecutors raging beyond measure and with all fear laid aside as though the world’s good fortune were smiling approvingly, while they say, “Peace and security” [1 Thessalonians 5:3]. Then the stars shall fall from the heaven, and the powers of heaven shall be moved, because many who seemed to shine brightly with grace will yield to the persecutors and will fall, and some of the most valiant faithful will be confounded. However, for this reason, according to Matthew and Mark it is said that this will take place after the tribulation of those days, not because these things will happen after that entire persecution has been brought to an end, but because the tribulation will come before, in order that certain people’s defection [from the faith] may follow. And because it will come to pass in such a way through all those days, therefore after the tribulation of those days, but all the same it will nonetheless come to pass in the same days.

 
(St. Augustine, Epistola CXCIX, par. 39; in Collectio Selecta Ss. Ecclesiae Patrum, vol. CXLVIII (Paris: Parent-Desbarres, 1835), pp. 127-128; underlining added. Professional translation commissioned by Novus Ordo Watch.)

https://novusordowatch.org/2021/11/saint-augustine-church-will-not-appear-during-tribulation/

Matthew 28:20

[20] Teaching them to observe all things whatsoever I have commanded you: and behold I am with you all days, even to the consummation of the world.

docentes eos servare omnia quaecuмque mandavi vobis : et ecce ego vobiscuм sum omnibus diebus, usque ad consummationem saeculi.

http://www.drbo.org/drl/chapter/47028.htm

Jeremiah 30:11

[11] For I am with thee, saith the Lord, to save thee: for I will utterly consume all the nations, among which I have scattered thee: but I will not utterly consume thee: but I will chastise thee in judgment, that thou mayst not seem to thyself innocent.

quoniam tecuм ego sum, ait Dominus, ut salvem te. Faciam enim consummationem in cunctis gentibus in quibus dispersi te : te autem non faciam in consummationem : sed castigabo te in judicio, ut non videaris tibi innoxius.

http://www.drbo.org/drl/chapter/28030.htm

[27] And he shall confirm the covenant with many, in one week: and in the half of the week the victim and the sacrifice shall fail: and there shall be in the temple the abomination of desolation: and the desolation shall continue even to the consummation, and to the end.

Confirmabit autem pactum multis hebdomada una : et in dimidio hebdomadis deficiet hostia et sacrificium : et erit in templo abominatio desolationis : et usque ad consummationem et finem perseverabit desolatio.

http://www.drbo.org/drl/chapter/32009.htm

[26] For then he ought to have suffered often from the beginning of the world: but now once at the end of ages, he hath appeared for the destruction of sin, by the sacrifice of himself.

alioquin oportebat eum frequenter pati ab origine mundi : nunc autem semel in consummatione saeculorum, ad destitutionem peccati, per hostiam suam apparuit.

http://www.drbo.org/drl/chapter/65009.htm

Hebrews 8:5-13

[5] Who serve unto the example and shadow of heavenly things. As it was answered to Moses, when he was to finish the tabernacle: See (saith he) that thou make all things according to the pattern which was shewn thee on the mount.
qui exemplari, et umbrae deserviunt caelestium. Sicut responsum est Moysi, cuм consummaret tabernaculum : Vide ( inquit) omnia facito secundum exemplar, quod tibi ostensum est in monte.

[6] But now he hath obtained a better ministry, by how much also he is a mediator of a better testament, which is established on better promises.
Nunc autem melius sortitus est ministerium, quanto et melioris testamenti mediator est, quod in melioribus repromissionibus sancitum est.

[7] For if that former had been faultless, there should not indeed a place have been sought for a second.
Nam si illud prius culpa vacasset, non utique secundi locus inquireretur.

[8] For finding fault with them, he saith: Behold, the days shall come, saith the Lord: and I will perfect unto the house of Israel, and unto the house of Juda, a new testament:
Vituperans enim eos dicit : Ecce dies venient, dicit Dominus : et consummabo super domum Israel, et super domum Juda, testamentum novum,

[9] Not according to the testament which I made to their fathers, on the day when I took them by the hand to lead them out of the land of Egypt: because they continued not in my testament: and I regarded them not, saith the Lord.
non secundum testamentum quod feci patribus eorum in die qua apprehendi manum eorum ut educerem illos de terra Aegypti : quoniam ipsi non permanserunt in testamento meo : et ego neglexi eos, dicit Dominus.

[10] For this is the testament which I will make to the house of Israel after those days, saith the Lord: I will give my laws into their mind, and in their heart will I write them: and I will be their God, and they shall be my people:
Quia hoc est testamentum quod disponam domui Israel post dies illos, dicit Dominus : dando leges meas in mentem eorum, et in corde eorum superscribam eas : et ero eis in Deum, et ipsi erunt mihi in populum :

[11] And they shall not teach every man his neighbour and every man his brother, saying, Know the Lord: for all shall know me from the least to the greatest of them:
et non docebit unusquisque proximum suum, et unusquisque fratrem suum, dicens : Cognosce Dominum : quoniam omnes scient me a minore usque ad majorem eorum :

[12] Because I will be merciful to their iniquities, and their sins I will remember no more.
quia propitius ero iniquitatibus eorum, et peccatorum eorum jam non memorabor.

[13] Now in saying a new, he hath made the former old. And that which decayeth and groweth old, is near its end.
Dicendo autem novum : veteravit prius. Quod autem antiquatur, et senescit, prope interitum est.



http://www.drbo.org/drl/chapter/65008.htm

Article 1. Whether any signs will precede the Lord's coming to judgment?

Objection 1. It would seem that the Lord's coming to judgment will not be preceded by any signs. Because it is written (1 Thessalonians 5:3): "When they shall say: Peace and security; then shall sudden destruction come upon them." Now there would be no peace and security if men were terrified by previous signs. Therefore signs will not precede that coming.

. . .

Reply to Objection 1. According to Augustine (Ad Hesych., Ep. lxxx) towards the end of the world there will be a general persecution of the good by the wicked: so that at the same time some will fear, namely the good, and some will be secure, namely the wicked. The words: "When they shall say: Peace and security," refer to the wicked, who will pay little heed to the signs of the coming judgment: while the words of Luke 21:26, "men withering away," etc., should be referred to the good.

We may also reply that all these signs that will happen about the time of the judgment are reckoned to occur within the time occupied by the judgment, so that the judgment day contains them all. Wherefore although men be terrified by the signs appearing about the judgment day, yet before those signs begin to appear the wicked will think themselves to be in peace and security, after the death of Antichrist and before the coming of Christ, seeing that the world is not at once destroyed, as they thought hitherto.

https://www.newadvent.org/summa/5073.htm

Quote from: St Augustine, The City of God (Book XX)

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That the last judgment, then, shall be administered by Jesus Christ in the manner predicted in the sacred writings is denied or doubted by no one, unless by those who, through some incredible animosity or blindness, decline to believe these writings, though already their truth is demonstrated to all the world. And at or in connection with that judgment the following events shall come to pass, as we have learned: Elias the Tishbite shall come; the Jєωs shall believe; Antichrist shall persecute; Christ shall judge; the dead shall rise; the good and the wicked shall be separated; the world shall be burned and renewed. All these things, we believe, shall come to pass; but how, or in what order, human understanding cannot perfectly teach us, but only the experience of the events themselves. My opinion, however, is, that they will happen in the order in which I have related them.

Commenting on the opening of the sixth seal Tyconius says:

Quote from: see attachment

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For it is not only in the last earthquake, when many [of the heavenly bodies = faithful] fall from heaven, that some will flee to the mountains, the mercy of the Lord. This always has happened from the passion of the Lord up until now. But at that time it will be greater, when the sign of the “falling away” will show that the day of the Lord is beginning.

Tyconius sees the day of the Lord beginning with the “falling away”, i.e. the sign given by the Apostle in 2 Thess 2. Hence the day of the Lord begins with and includes the falling away, the revelation of the man of sin, the reign of Antichrist. Maybe that's how and why St. Augustine, too, says that the reign of Antichrist may be included in the events that shall come to pass at the final judgment (see Reply #93).

Quote from: Jerome, Commentary in Isaiah 13:12

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In consummatione mundi, quando orbis redactus fuerit in solitudinem, et obtenebratus sol in ortu suo, et luna splendorem suum non dederit, tanta fient ab Antichristo signa atque portenta, ut iniquitate crescente, refrigescat charitas multorum, ad decipiendos etiam si fieri potest electos Dei (Matth. XXIV).

mlat.uzh.ch

St. Jerome, commenting on Isaiah 13:12, says that during the consummation of the world the sun will be darkened, the moon will not give it's splendor, and Antichrist will present his signs and fictions, such that growing wickedness will make freeze the charity of many, to deceive (if possible) even the elect.

St. Jerome clearly believes that the consummation of the world includes the time of the reign of Antichrist, as this quote shows and as his Commentary in Matthew shows (see Reply #137).

Various Church Fathers say that the darkened sun and moon signify "Church in eclipse" (though not necessarily using these words). In his Commentary on Daniel, the wording of Jerome about the Antichrist predecessor Antiochus Epiphanes is "the religion of God suffered an eclipse".