It may have simply been the author’s comment. A redaction is an edit or revision to an original text. Meyer comments,1
Parenthetical observation by the evangelist, to impress upon his readers the precise point of time indicated by Jesus at which the flight is to take place upon the then impending (not already present, Hug, Bleek) catastrophe.
This is a synoptic parallel shared among the three Synoptic Gospels, i.e. Matthew, Mark, and Luke. However, you did not cite the one which occurs in Luke.
In Luke 21:20–21, it is written,
20 “But when you see Jerusalem surrounded by armies, then know that its desolation is near. 21 “Then let those who are in Judea flee to the mountains, let those who are in the midst of her depart, and let not those who are in the country enter her. NKJV, ©1982
Thus, it’s reasonable to conclude that the abomination of desolation occurs very soon after armies surround Jerusalem, something which happened in 70 A.D. when Jerusalem was encompassed and conquered by the Romans, as Eusebius testified,2
3 But the people of the church in Jerusalem had been commanded by a revelation, vouchsafed to approved men there before the war, to leave the city and to dwell in a certain town of Perea called Pella. And when those that believed in Christ had come thither from Jerusalem, then, as if the royal city of the Jews and the whole land of Judea were entirely destitute of holy men, the judgment of God at length overtook those who had committed such outrages against Christ and his apostles, and totally destroyed that generation of impious men.
4 But the number of calamities which everywhere fell upon the nation at that time; the extreme misfortunes to which the inhabitants of Judea were especially subjected, the thousands of men, as well as women and children, that perished by the sword, by famine, and by other forms of death innumerable,—all these things, as well as the many great sieges which were carried on against the cities of Judea, and the excessive. sufferings endured by those that fled to Jerusalem itself, as to a city of perfect safety, and finally the general course of the whole war, as well as its particular occurrences in detail, and how at last the abomination of desolation, proclaimed by the prophets, stood in the very temple of God, so celebrated of old, the temple which was now awaiting its total and final destruction by fire,—all these things any one that wishes may find accurately described in the history written by Josephus.3
Josephus also wrote the following,4
And now the Romans, upon the flight of the seditious into the city, and upon the burning of the holy house itself, and of all the buildings round about it, brought their ensigns to the temple and set them over against its eastern gate; and there did they offer sacrifices to them, and there did they make Titus imperator with the greatest acclamations of joy.
Tertullian wrote the following with respect to the Roman signum or “standard”:5
The entire Roman camp religion worships the standards, swears by the standards, sets the standards over all gods.
Religio Romanorum tota castrensis signa veneratur, signa iurat, signa omnibus deis praeponit.
1 Meyer, p. 415
2 Eusebius, Book 3, Ch. 5, §3–4 (Migne, p. 221, 224; McGiffert, p. 138)
Γʹ ἀλλὰ καὶ τοῦ λαοῦ τῆς ἐν Ἱεροσολύμοις ἐκκλησίας κατά τινα χρησμὸν τοῖς αὐτόθι δοκίμοις δι' ἀποκαλύψεως ἐκδοθέντα πρὸ τοῦ πολέμου μεταναστῆναι τῆς πόλεως καί τινα τῆς Περαίας πόλιν οἰκεῖν κεκελευσμένου, Πέλλαν αὐτὴν ὀνομάζουσιν, ἐν ἧ τῶν εἰς Χριστὸν πεπιστευκότων ἀπὸ τῆς Ἱερουσαλὴμ μετῳκισμένων, ὡς ἂν παντελῶς ἐπιλελοιπότων ἁγίων ἀνδρῶν αὐτήν τε τὴν Ἰουδαίων βασιλικὴν μητρόπολιν καὶ σύμπασαν τὴν Ἰουδαίαν γῆν, ἡ ἐκ θεοῦ δίκη λοιπὸν αὐτοὺς ἅτε τοσαῦτα εἴς τε τὸν Χριστὸν καὶ τοὺς ἀποστόλους αὐτοῦ παρηνομηκότας μετῄει, τῶν ἀσεβῶν ἄρδην τὴν
Δʹ ἐκείνην ἐξ ἀνθρώπων ἀφανίζουσα. ὅσα μὲν οὖν τηνικάδε κατὰ
πάντα τόπον ὅλῳ τῷ ἔθνει συνερρύη κακά, ὅπως τε μάλιστα οἱ τῆς Ἰουδαίας
οἰκήτορες εἰς ἔσχατα περιηλάθησαν συμφορῶν, ὁπόσαι τε μυριάδες ἡβηδὸν γυναιξὶν
ἅμα καὶ παισὶ ξίφει καὶ λιμῷ καὶ μυρίοις ἄλλοις εἴδεσι περιπεπτώκασιν θανάτου,
πόλεών τε Ἰουδαϊκῶν ὅσαι τε καὶ οἷαι γεγόνασιν πολιορκίαι, ἀλλὰ καὶ ὁπόσα οἱ ἐπ'
αὐτὴν Ἱερουσαλὴμ ὡς ἂν ἐπὶ μητρόπολιν ὀχυρωτάτην καταπεφευγότες δεινὰ καὶ πέρα δεινῶν ἑοράκασι, τοῦ τε παντὸς πολέμου τὸν τρόπον καὶ τῶν ἐν τούτῳ γεγενημένων ἐν μέρει ἕκαστα, καὶ ὡς ἐπὶ τέλει τὸ πρὸς τῶν προφητῶν ἀνηγορευμένον βδέλυγμα τῆς ἐρημώσεως ἐν αὐτῷ κατέστη τῷ πάλαι τοῦ θεοῦ περιβοήτῳ νεῷ, παντελῆ φθορὰν καὶ ἀφανισμὸν ἔσχατον τὸν διὰ πυρὸς ὑπομείναντι, πάρεστιν ὅτῳ φίλον ἐπ' ἀκριβὲς ἐκ τῆς τῷ Ἰωσήπῳ γραφείσης ἀναλέξασθαι ἱστορίας·
3 Josephus, Wars of the Jews, Books 5–6
4 id., Book 6, Ch. 6 (§316–317) (Niese, p. 555; Whiston, p. 681)
Ῥωμαῖοι δὲ τῶν μὲν στασιαστῶν καταπεφευγότων εἰς τὴν πόλιν, καιομένου δὲ αὐτοῦ τε τοῦ ναοῦ καὶ τῶν πέριξ ἁπάντων, κομίσαντες τὰς σημαίας εἰς τὸ ἱερὸν καὶ θέμενοι τῆς ἀνατολικῆς πύλης ἄντικρυς ἔθυσάν τε αὐταῖς αὐτόθι καὶ τὸν Τίτον μετὰ μεγίστων εὐφημιῶν ἀπέφηναν αὐτοκράτορα.
5 Apologetic, Ch. 16 (Migne, p. 367–368)
Eusebius. “Church History.” A Select Library of Nicene and Post-Nicene Fathers of the Christian Church. Trans. McGiffert, Arthur Cushman. Ed. Schaff, Philip; Wace, Henry. Vol. 1. New York: Christian Literature, 1890.
Eusebius. «ΕΚΚΛΗΣΙΑΣΤΙΚΗΣ ΙΣΤΟΡΙΑΣ» (“Ecclesiastical History”). Patrologiæ Cursus Completus: Series Græca. Ed. Migne, Jacques Paul. Vol. 20. Petit-Montrouge: Imprimerie Catholique, 1857.
Flavius Josephus. Flavii Iosephi Opera. Ed. Niese, Benedictus. Vol. 6. Berlin: Weidmann, 1894.
Flavius Josephus. The Complete Works of Flavius-Josephus the Celebrated Jewish Historian. Trans. Whiston, William. Chicago: Thompson, 1901.
Meyer, Heinrich August Wilhelm. Critical and Exegetical Handbook to the Gospel of Matthew. Trans. Christie, Peter. Ed. Crombie, Frederick; Stewart, William. New York: Funk, 1884.
Tertullian. “Apologeticus” (“Apology”). Patrologiæ Cursus Completus: Series Prima. Ed. Migne, Jacques Paul. Vol. 1. Petit-Montrouge: Imprimerie Catholique, 1844.
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