They did not know what to begin or what to take up. “Neither by spirit.” He does not mean a spirit of falsehood, but that spirit which manifested itself in members of the Church.
This is the spirit of prophecy, or of revelation and insight into the mysteries of God. So all the holy Fathers understand it: Chrysostom, Theodoret, Damascene, Oecumenius, and Theophylact.
In Christian assemblies the Spirit would come upon certain persons. They would rise and begin inspired speech. This speech chiefly concerned the edification of the Church in faith and love.
Yet it could also embrace the past and foresee the future. There were persons especially distinguished by insight into the future.
When St. Paul said of himself that the Spirit spoke throughout the Churches that bonds and sufferings awaited him (Acts 20:23), he meant this prophetic spirit.
It was manifested in the Churches of that time because of the purity of faith and life among the first believers.
Whether someone spoke in this spirit among the Thessalonians about the coming of the day of the Lord cannot be asserted. Perhaps no one spoke so.
Perhaps St. Paul, only anticipating such a case, says: even if someone should begin to speak to you in a prophetic spirit, do not believe it. He says this to cut off every possibility of deception.
Thus St. Chrysostom says: “Even if someone having the Spirit of prophecy should tell you this, do not believe it.
For when I was with you, I explained to you everything concerning this matter. Therefore you should not change your thoughts concerning what you were clearly taught.”
From the fact that a letter supposedly written by the Apostle and a word supposedly spoken by him were actually presented to confirm the thought that the day of the Lord had come, one might probably conclude something.
There may indeed have been claims about such inspirations of the prophetic spirit. Yet an obvious point considerably weakens this probability.
Here, the word and the letter are presented as belonging to St. Paul, but the phrase “neither by spirit” cannot in any way refer to him.
This forces us to see a special nuance in the meaning of this phrase. The Apostle wished to express something like this: do not believe when my supposed word and my supposed letter are falsely presented to you.
But even if someone known among you as a prophet should truly begin to teach this, do not accept his words. In meaning this resembles the Apostle’s words to the Galatians: “Even if an angel from heaven” (Gal 1:8).
If anyone wishes to accept that the Thessalonians actually heard inspirations from those speaking in a prophetic spirit, then one must understand “as if.”
That is, as if in a prophetic spirit, and not actually in a prophetic spirit. For the true spirit of prophecy does not lie.
St. Damascene writes: “Let no one terrify you, not even one who appears to speak by the spirit of revelation.” Theodoret expresses it more sharply: “If they present themselves as seers and prophets, we do not command you to believe.”
This could have happened without any special evil intent. Someone might reflect that the day of the Lord will not come with observation.
Having established himself in the decision to await, according to the Lord’s word, His appearing at every hour, he might pass to the conclusion that this is already the case: the day is at hand.
Then, inspired by this thought, he might speak about it in the assembly. Such a person could seem to speak in the Spirit, while in fact he spoke from himself.
Not every inspired speech is from the Spirit. So that believers would not be exposed to the danger of error because of this, the gift of discerning spirits remained in the Church.
“Neither by word, nor by letter.” Some suppose that “word” here is the word of the Lord Himself, handed down by tradition, or His word written in the Gospel (Mt 24; Mk 13; Lk 21).
But it is obvious that “word” here must be understood as a word proceeding from the Apostle Paul, just as “letter” must be so understood.
Only such words and letters were falsely ascribed to him, as the words “as if from us” show. Below, in verse 15, the Apostle presents his own word and letter as the only source of divine revelation for the Thessalonians.
And now, amid false thoughts about the coming of the day of the Lord, some were saying, “The Apostle himself said so.” Others said, “It is written so in his letter.”
Or perhaps one said, “I heard it,” and another said, “Here, look, there is also a letter.” The word “sent” is not in the Greek text.
It has only “as if from us.” Therefore almost everyone relates this phrase not only to the letter, but also to the word.
There are some who relate it to the spirit as well, but this confuses and darkens the speech. “As though it had already come,” from the Greek, means as though the day of the Lord had already arrived.
This is the last day, the day of the final determination of the lot of all and of each. In this lay all the error in the opinions of the Thessalonians.
One must always await the coming of the Lord, according to the commandment of the Lord Himself. But one must not determine the moment of the coming, because no one can know it except God.
The Thessalonians determined it, and by this they sinned, appropriating God’s right to themselves. The Apostle instructs them, speaking as though saying: one cannot decide this way, and you must not do so.
Do not do so, no matter who may persuade you to it. It is not evident that there were any malicious disseminators of falsehood. Otherwise the Apostle’s word would have been stronger and more definite.
The thought could have spread as if by accident. Someone said in the assembly, “Behold, the Lord is about to come!” Another confirmed it: “Yes, and the Apostle supposedly said so.”
A third added, “And it is written so in his letter,” or, “There is also a letter about this.” Then talk went everywhere and brought everyone into confusion.
It occurred to no one to examine the matter. The Apostle’s word about the suddenness of the Lord’s appearing seemed to justify the conclusion that it was at the doors.
Oecumenius suggests that they were troubled through ignorance and timidity.