Little children, it is a last hour; and just as you heard that the Antichrist is coming, even now many antichrists have come to be—[from which] we know that it is a last hour. (1 Jn. 2:18) Literal Translation
John did not say “it is THE last hour”, the definite article is lacking which allows for a qualitative or anarthrous reading “it is last hour” or “a last hour”. John does not assert “the last hour has fully come, but that conditions characteristic of the last hour are now being observed.” The apostasy then occurring in his church happens also just before the Antichrist makes his appearance. “Just as…even now” suggests an analogy, events foreshadow the coming of the Antichrist in the future. The antichrists are evidence, from which we “know it is a last hour”.
If John were predicting the Antichrist would soon appear, it follows he would have given instructions on what to do at that time. Nothing like that is in the context.
This is “the apostasy” Paul says, “comes first” before the arrival of the Man of Sin (2 Thess. 2:3). John reveals what will happen:
They went out from us, but they were not of us; for if they had been of us, they would have continued with us; but they went out that they might be made manifest, that none of them were of us. (1 Jn. 2:19 NKJ)
These were Tares sown among the Wheat (Mt. 13:24-30, 36-42). Just as Tares resemble Wheat at first, so too antichrists appear to be Christians, but as they mature their true identity is revealed. It is implied the counterfeit was so good, only their leaving manifested their true identity. It follows the signs and wonders they did in John’s church were indistinguishable from those Christians did (cp. Mt. 7:22-23; 2 Thess. 2:9-10). However, John says they always had an “inner witness” something was not right, their anointing (the Holy Spirit) enabled them to “know all things”, that “no lie is of the truth” (1 John 2:20-21).
The followers of Cerinthus or some Jewish Christian or early Docetic Gnostics were the likely antichrist’s John described, denying the Father and the Son, and Jesus’ incarnation (1 John 2:22-23).
Mainline Pentecostal churches do not deny Christ or His Incarnation so they cannot be these antichrists, regardless what one thinks about their signs and wonders. But it follows from John’s description that during the great “falling away” many will depart to follow the new religion of the miracle working “man of sin”, the genitive implies preaching against sin is not what he does. Sinfully denying Jesus is the Christ, disputing Trinitarian teaching about Father and Son, follows from 2 Thess. 2:4 “who opposes and exalts himself above all that is called God.”
Notes
The assertion (v. 18a). “It is the last hour” (ἐσχάτη ὥρα ἐστίν) marks the crucial situation. The term “last hour” obviously was not intended as a literal chronological assertion. Since the original does not have the definite article, two renderings, “the last hour,” or “a last hour,” are possible. In support of the former rendering, commonly used in English versions, it is held that the expression is sufficiently definite without the article, “for there can be only one last hour.” Or it may be viewed as a technical term that does not need the definite article.2 But some like Westcott3 insist on rendering the phrase “a last hour.” Since this exact expression occurs only here in the New Testament, Lenski feels that it cannot be treated as a well-known concept that needed no article, and so he asserts, “The term is plainly qualitative.”4
2 H. E. Dana and Julius R. Mantey, A Manual Grammar of the Greek New Testament (reprint, New York: Macmillan Co., 1967), p. 149.
3 Brooke Foss Westcott, The Epistles of St. John: The Greek Text with Notes and Essays (reprint, Grand Rapids: Wm. B. Eerdmans Publishing Co., 1950), p. 68.
4 R. C. H. Lenski, The Interpretation of the Epistles of St. Peter, St. John and St. Jude (1945; reprint, Minneapolis: Augsburg Publishing House, 1966), p. 429.Hiebert, D. E. (1989). An Expositional Study of 1 John Part 4 (of 10 parts): An Exposition of 1 John 2:18–28. Bibliotheca Sacra, 146, 77–78.