You said:
"In this verse it refers to Jews forsaking or falling away (departing from) the teachings of Moses. I believe it should be understood similarly in 2 Thess 2:3 as referring to a mass falling away or departure from the faith."
The problem as I see it is that departing from the faith is not mention in 2 Thes or 1 Thes. Also, Paul uses the verb APOSTAMAI to refer to the departing from the faith, not the noun, as here. And Paul finds it necessary to add to the word APOSTAMAI "from the faith" to indicate what kind of falling away he is referring to. See my post on APOSTAMAI out here.
So in 2 Thes 2.3 Paul does not use a modifying phrase (such as "from the faith" or "from Moses") and does use the articular noun in stead of the verb. Without a modifying phrase to APOSTASIA, it has no meaning of rebellion, apostasy, or departure from the faith. I am going off memory here but the cognate verb of APOSTASIA is found 15 or so times in the NT, and 12 or so of those refer to a physical departure. This is why many non Pre Tribbers reject the use of the verb as supplying a meaning to APOSTASIA. This rejection of the verb is a semantical adnormality.
I don't believe we are still on this topic-here, listen to Barnes.
For that day shall not come, except there come a falling away first - Until an apostasy (ἀποστασία apostasia) shall have occurred - the great apostasy.
There is scarcely any passage of the New Testament which has given occasion to greater diversity of opinion than this.
Though the reference seems to be plain, and there is scarcely any prophecy of the Bible apparently more obvious and easy in its general interpretation;
yet it is proper to mention some of the opinions which have been entertained of it.
Some have referred it to a great apostasy from the Christian church, particularly on account of persecution, which would occur before the destruction of Jerusalem. The “coming of the Lord” they suppose refers to the destruction of the holy city, and according to this, the meaning is, that there would be a great apostasy before that event would take place. Of this opinion was Vitringa, who refers the “apostasy” to a great defection from the faith which took place between the time of Nero and Trajan.
Whitby also refers it to an event which was to take place before the destruction of Jerusalem, and supposes that the apostasy would consist in a return from the Christian to the Jewish faith by multitudes of professed converts. The “man of sin,” according to him, means the Jewish nation, so characterized on account of its eminent wickedness.
Hammond explains the apostasy by the defection to the Gnostics, by the arts of Simon Magus, whom he supposes to be the man of sin, and by the “day of the Lord” he also understands the destruction of Jerusalem.
Grotius takes Caius Caesar or Caligula, to be the man of sin, and by the apostasy he understands his abominable wickedness. In the beginning of his government, he says, his plans of iniquity were concealed, and the hopes of all were excited in regard to his reign; but his secret iniquity was subsequently “revealed,” and his true character understood.
Wetstein understands by the “man of sin,” that it referred to Titus and the Flavian house. He says that he does not understand it of the Roman Pontiff, who “is not one such as the demonstrative pronoun thrice repeated designates, and who neither sits in the temple of God, nor calls himself God, nor Caius, nor Simon Gioriae, nor any Jewish impostor, nor Simon Magus.”
Koppe refers it to the King mentioned in Dan_11:36. According to him, the reference is to a great apostasy of the Jews from the worship of God, and the “man of sin” is the Jewish people.
Others have supposed that the reference is to Muhammed, and that the main characteristics of the prophecy may be found in him.
Of the Papists, a part affirm that the apostasy is the falling away from Rome in the time of the Reformation, but the greater portion suppose that the allusion is to Antichrist, who, they say, will appear in the world before the great day of judgment, to combat religion and the saints. See these opinions stated at length, and examined, in Dr. Newton on the Prophecies, Dissertation xxii.
Some more recent expositors have referred it to Napoleon Bonaparte, and some (as Oldshausen) suppose that it refers to some one who has not yet appeared, in whom all the characteristics here specified will be found united.
Most Protestant commentators have referred it to the great apostasy under the papacy, and, by the “man of sin,” they suppose there is allusion to the Roman Pontiff, the Pope. It is evident that we are in better circumstances to understand the passage than those were who immediately succeeded the apostles.
Eighteen hundred years have passed (written circa 1880’s) away since the Epistle was written, and the “day of the Lord” has not yet come, and we have an opportunity of inquiring, whether in all that long tract of time any one man can be found, or any series of men have arisen, to whom the description here given is applicable. If so, it is in accordance with all the proper rules of interpreting prophecy, to make such an application. If it is fairly applicable to the papacy, and cannot be applied in its great features to anything else, it is proper to regard it as having such an original reference. Happily, the expressions which are used by the apostle are, in themselves, not difficult of interpretation, and all that the expositor has to do is, to ascertain whether in any one great apostasy all the things here mentioned have occurred. If so, it is fair to apply the prophecy to such an event;
if not so, we must wait still for its fulfillment.
The word rendered “falling away” (ἀποστασία apostasia, apostasy), is of so general a character, that it may be applied to any departure from the faith as it was received in the time of the apostles.
It occurs in the New Testament only here and in Act_21:21, where it is rendered “to forsake” -
“thou teachest all the Jews which are among us to forsake Moses” - apostasy from Moses - ἀποστασίαν ἀπὸ Μωῦσέως apostasian apo Mōuseōs.
The word means a departing from, or a defection; see the verb used in
1Ti_4:1, “Some shall depart from the faith” -
ἀποστήσονται apostēsontai;
1Ti 4:1 The Coming Apostasy
¶ Now the Spirit explicitly says that in the last times some will depart [ἀφίστημι] from the faith, paying attention to deceitful spirits and teachings of demons,
compare the notes on that passage; see also Heb_3:12; Luk_8:13; Act_5:37. The reference here is evidently to some general falling away, or to some great religious apostasy that was to occur, and which would be under one head, leader, or dynasty, and which would involve many in the same departure from the faith, and in the same destruction.
The use of the article here, “the apostasy” (Greek), Erasmus remarks, “signifies that great and before-predicted apostasy.” It is evidently emphatic, showing that there had been a reference to this before, or that they understood well that there was to be such an apostasy. Paul says 2Th_2:5, that when he was with them, he had told them of these things. The writers in the New Testament often speak of such a defection under the name of Antichrist; see Rev_13:14; 1Jo_2:18, 1Jo_2:22; 1Jo_4:3; 2Jo_1:7.
J.
