Earl Doherty, seeking to read 1 John in conformity with his general thesis that the NT epistles presuppose a mystical/celestial Jesus Christ rather than a historical Jesus of Nazareth, suggested that this epistle was originally mythicist, but through a later redaction was made to conform to the Gospel ideas of a historical Jesus. This reading of 1 John is not convincing, because there are no obvious indications of later editing. The language is raw, unpolished, sometimes clumsily repetitive, but there is a unity of purpose and theme throughout. It is not a letter, of course, but some kind of written testimony, declaration, or manifesto. And it emerged out of an identity crisis for the community, which explains the severe, all-or-nothing intensity of its message.
Any sensible reading of 1 John must explain why a community that was, on the historicist view, founded on (or at least in accordance with) a belief that Jesus of Nazareth was the messiah, would have suffered a major schism over this very belief. It is not merely the supposedly anti-docetic statement in 4:2 that the author brings to the fore, but simply the idea that Jesus was the Christ. The two statements seem to have the same weight, the same basic meaning for him. A faction of docetists can hardly explain the traumatic rupture of the community over the most basic proposition of Christianity itself, that Jesus is the Christ.1 John 2: 18-19
Children, it is the last hour; and as you have heard that antichrist is coming, so now many antichrists have come; therefore we know that it is the last hour. 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 it might be plain that they all are not of us. But you have been anointed by the Holy One, and you know all things. I write to you, not because you do not know the truth, but because you know it, and know that no lie is of the truth. Who is the liar but he who denies that Jesus is the Christ? This is the antichrist, he who denies the Father and the Son. 23 No one who denies the Son has the Father.
Assuming an originally celestial/mystical rather than a historical Jesus, it is possible that 1 John reflects a recent acceptance of the story of Jesus of Nazareth, which caused a hateful division in the community and a major schism.
There are three parts to this analysis. (1) The author is historicist about Jesus; (2) the author's (or the church's) original "commandment" or teaching about Jesus Christ was not historicist, but celestial/mystical; and (3) the allegedly deceiving schismatics who left the church did so because they refused to accept the new teaching about Jesus.
1. The author of 1 John believed in a historical Jesus--
who was not merely called "Jesus Christ" but who was the Christ 2.22
who was the only Son of God 4:15
who was sent into the world "in the flesh" 4:2
who was righteous 2:1
who walked according to the commandments 2:6
who laid down his life for others as a model for what believers ought to do 3:16
whose bloody death was an atoning sacrifice for the sins of the world 1:7, 2:1
who came not only by the water of baptism but by the blood of sacrifice 5:7-8
and who is known to believers not only by the testimony of God but also by the testimony of human beings 5:9
Admittedly, this is a minimally historical Jesus. But it is a considerable advance beyond Paul, who never wrote of Jesus as a moral exemplar. Most important, the primary affirmation that Jesus is the Christ aligns with Mark 8:39 and with the entire Gospels/Acts account of Jesus. But it has no antecedent in Paul, who never said "Jesus is the Christ." The original gospel of Jesus Christ was not a gospel that Jesus is the Christ. This leads us to the second layer in 1 John:
2. The author presupposes and reaffirms an earlier teaching "from the beginning," given through the Spirit and through the anointing (2:20) and through the water (of baptism), through which the believers "know all things," and it is simply through this original knowledge of the Father/the Son/the Spirit given in the anointing they received that they are able to accept the "testimony of human beings" (5:9) about Jesus. The historical Jesus is grafted onto the celestial/mystical Jesus Christ.
3. The author is writing in order to refute "those who would deceive you" (2:26), who make three specific denials that amount to the same thing: (1) they deny that Jesus is the Christ (2:22); (2) they deny that Jesus Christ has come in the flesh (4:2); and therefore (3) they deny Jesus altogether. In denying the Son, they deny the Father, and make God a liar, since it is God himself who provided the testimony about his own Son (5:10). These denials result in the complete loss of communion with the author, who is "from God" (4:6), and therefore they are completely in darkness, on team Satan, as unloving as Cain, etc. In reality, these people probably had their own legitimate reasons not to accept the new stories, and we're very angry and disruptive about it. Hence the drama of 1 John.
This text seems to have a very significant Christological purpose, in addition to the moral and cosmically dualistic themes for which it is generally known. The author skillfully weaves the Christological argument along with the moral and theological argument, so that the reader comes away completely unable to disentangle the desire to maintain fellowship with a loving God from the necessary faith in a specific, historical Jesus. Perhaps the most telling sign of the author's underhanded purpose is his self-contradictory hesitation over whether or not he is offering the church a "new commandment":
First a denial, then a hesitation. Then he finally comes around to what the new commandment is:1 John 2: 7-8
Beloved, I am writing you no new commandment, but an old commandment which you had from the beginning; the old commandment is the word which you have heard. Yet I am writing you a new commandment, which is true in him and in you, because the darkness is passing away and the true light is already shining.
There is nothing new about the commandment to love one another. What is perhaps new is the commandment to believe in the name, because these new stories are coming out about who Jesus is. If the figure of Jesus had never changed, what would be the struggle, or the controversy, about believing that Jesus came in the flesh as the Christ?1 John 3:23
And this is his commandment, that we should believe in the name of his Son Jesus Christ and love one another, just as he has commanded us.
The author of 1 John is absolutely insistent that he is only preaching the original faith, even though acceptance of something new is being demanded. It's a tangled, underhanded text.