In the course of his instructions for the saints at Thessalonica, the apostle speaks of the coming and of the day of the Lord.
The coming is his common subject. He speaks of it in chapters 2, 3, 4, and 5, and intimates it in chapter 1. But he also brings in the day in ch. 5.
This would materially dispose the mind to confound or identify the two-specially a Jewish mind, or the mind of one brought to the faith of Christ from the Synagogue, as many at Thessalonica were. And the Lord, in Matt. 24, I might also acknowledge, does identify them. And I might also allow that Peter does not propose to keep them separate in his argument in 2 Peter 3.
But this is not to be wondered at. The Lord teaching the remnant, or the Israel of God, the earthly people might well have such terms or such thoughts in that condition. The time had not then come for, distinguishing earthly and heavenly calling, or for speaking of the rapture. And Peter is more occupied (properly so on account of his whole subject or contexts) with the judgments that are to introduce and to close the kingdom, than with the kingdom itself, or the heavenly deportment in the kingdom.
Paul, however, was, characteristically, the minister of the Church. He is made, under the Holy Ghost, the witness of her calling, in a very peculiar way. We might, therefore, expect all about her from him; and to find things that differ distinguished, things that were before obscure cleared up, and things before kept secret made known. And so we do. The Epistles to the Thessalonians witness this—and witness this in this very matter of the rapture of the saints, or of the distinction between the coming and the day of Christ. Having spoken of the coming of the Lord in the 1St Epistle, in various ways of light and comfort to the saints, and having then spoken of the day of the Lord in terms of alarm and warning, the Thessalonians might well be supposed to be put into some trial and temptation because of all this. They were but young in the knowledge of the Lord, and would not know how to deal with these communications. The apostle, therefore, in his 2nd letter, sets himself in their behalf, to distinguish things that differ; to separate the coming from the day; to comfort and assure themselves by the one, and to know that the other in its terms was to meet its due and proper object, and not those who were chosen, and sanctified, and saved, and called, to the obtaining of the glory of the Lord Jesus Christ. And again, he commands them to be comforted. (2 Thess. 2)