2 Thessalonians 2:2

That ye be not soon shaken in mind
Or "from your mind or sense", as the Vulgate Latin version; or "from the solidity of sense", as the Arabic version; that is, from what they had received in their minds, and was their sense and judgment, and which they had embraced as articles of faith; that they would not be like a wave of the sea, tossed to and fro with every wind of doctrine; or be moved from the hope of the Gospel, from any fundamental article of it, and from that which respects the second coming of Christ particularly; and especially, that they would not be quickly and easily moved from it; see ( Galatians 1:6 )

or be troubled;
thrown into consternation and surprise, for though the coming of Christ will not be terrible to saints, as it will be to sinners; yet there is something in it that is awful and solemn, and fills with concern; and to be told of it as at that instant might be surprising and shocking: the several ways in which their minds might be troubled and distressed with such an account are enumerated by the apostle, that they might guard against them, and not be imposed upon by them:

neither by spirit;
by a prophetic spirit, by pretensions to a revelation from the Spirit, fixing the precise time of Christ's coming, which should not be heeded or attended to; since his coming will be as a thief in the night:

nor by word:
by reason and a show of it, by arguments drawn from it, which may carry in them a show of probability; by enticing words of man's wisdom; by arithmetical or astronomical calculations; or by pretensions to a word, a tradition of Christ or his apostles, as if they had received it "viva voce", by word of mouth from any of them:

nor by letter, as from us;
by forging a letter and counterfeiting their hands, for such practices began to be used very early; spurious epistles of the Apostle Paul were carried about, which obliged him to take a method whereby his genuine letters might be known; see ( 2 Thessalonians 3:17 2 Thessalonians 3:18 ) or he may have respect in this clause to his former epistle, wherein he had said some things concerning the Coming of Christ, which had been either wrongly represented, or not understood; and as if his sense was, that it would be while he and others then living were alive and on the spot: wherefore he would not have them neither give heed to any enthusiastic spirits, nor to any plausible reasonings of men, or unwritten traditions; nor to any letters in his name, or in the name of any of the apostles; nor even to his former letter to them, as though it contained any such thing in it,

as that the day of Christ is at hand;
or is at this instant just now coming on; as if it would be within that year, in some certain month, and on some certain day in it; which notion the apostle would have them by no means give into, for these reasons, because should Christ not come, as there was no reason to believe he would in so short a time, they would be tempted to disbelieve his coming at all, at least be very indifferent about it; and since if it did not prove true, they might be led to conclude there was nothing true in the Christian doctrine and religion; and besides, such a notion of the speedy coming of Christ would tend to indulge the idle and disorderly persons among them in their sloth and negligence: and now for these, and for the weighty reasons he gives in the next verse, he dissuades them from imbibing such a tenet; for though the coming of Christ is sometimes said to be drawing nigh, and to be quickly, yet so it might be, and not at that instant; besides, such expressions are used with respect to God, with whom a thousand years are as one day, and one day as a thousand years; and because the Gospel times, or times of the Messiah, are the last days, there will be no other dispensation of things until the second coming of Christ; and chiefly they are used to keep up the faith, and awaken the hope and expectation of the saints with respect to it. The Alexandrian copy, and some others, read, "the day of the Lord"; and so the Vulgate Latin version; and accordingly the Syriac and Ethiopic versions, "the day of our Lord".