“The Lord is at hand.”—Phil. 4:5.
“Be not soon shaken in mind, nor troubled, neither by spirit, nor by word, nor by letter, as from us, as that the day of Christ is at hand.”—2 Thess. 2:2.
Every thing with respect to degrees is what it is by comparison. Taking into consideration the whole of time, the coming of Christ was “at hand.” There is reason to believe from this, and many other passages of the New Testament, that the sacred writers considered themselves as having passed the meridian of time, and entered into the afternoon of the world, as we may say. Such appears to be the import of the following, among other passages: “God hath in these last days spoken to us by his Son.” “Once in the end of the world hath he appeared to put away sin by the sacrifice of himself.”—“Upon whom the ends of the world are come.”—“The coming of the Lord draweth nigh.”—“Surely I come quickly.”
But taking into consideration only a single generation, the day of Christ was not at hand. The Thessalonians, though a very amiable people, were by some means mistaken on this subject, so as to expect that the end of the world would take place in their lifetime, or within a very few years To correct this error, which might have been productive of very serious evils, was a principal design of the Second Epistle to that people.
Fuller, A. G. (1988). The Complete Works of Andrew Fuller: Memoirs, Sermons, Etc. (J. Belcher, Ed.) (Vol. 1, pp. 667–684). Harrisonburg, VA: Sprinkle Publications.