That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand. Be not soon shaken in mind - Απο του νοος· From the mind; i.e. that they should retain the persuasion they had of the truths which he had before delivered to them; that they should still hold the same opinions, and hold fast the doctrines which they had been taught.
Neither by spirit - Any pretended revelation.
Nor by word - Any thing which any person may profess to have heard the apostle speak.
Nor by letter - Either the former one which he had sent, some passages of which have been misconceived and misconstrued; or by any other letter, as from us - pretending to have been written by us, the apostles, containing predictions of this kind. There is a diversity of opinion among critics concerning this last clause, some supposing that it refers simply to the first epistle; others supposing that a forged epistle is intended. I have joined the two senses. The word σαλευθηναι, to be shaken, signifies to be agitated as a ship at sea in a storm, and strongly marks the confusion and distress which the Thessalonians had felt in their false apprehension of this coming of Christ.
As that the day of Christ is at hand - In the preface to this epistle I have given a general view of the meaning of the phrase the coming of Christ. Now the question is: Whether does the apostle mean, the coming of Christ to execute judgment upon the Jews, and destroy their polity, or his coming at the end of time, to judge the world? There are certainly many expressions in the following verses that may be applied indifferently to either, and some seem to apply to the one, and not to the other; and yet the whole can scarcely be so interpreted as to suit any one of these comings exclusively. This is precisely the case with the predictions of our Lord relative to these great events; one is used to point out and illustrate the other. On this ground I am led to think that the apostle, in the following confessedly obscure words, has both these in view, speaking of none of them exclusively; for it is the custom of the inspired penmen, or rather of that Spirit by which they spoke, to point out as many certain events by one prediction as it was possible to do, and to choose the figures, metaphors, and similes accordingly; and thus, from the beginning, God has pointed out the things that were not by the things that then existed, making the one the types or significations of the other. As the apostle spoke by the same Spirit, he most probably followed the same plan; and thus the following prophecy is to be interpreted and understood.