Who Was the Apostle John Writing Against in His Letters?

Polycarp provides reliable evidence that John may have written against Cerinthus or at least those connected to him in 1 and 2 John. John's Gospel may also counter Cerinthus and other heretics too.

In two of the Johannine epistles (1 and 2 John), we encounter a strong polemic against certain opponents who were threatening the early Christian community. But who exactly were these adversaries that the elderly apostle was so concerned about?

Characteristics of John's Opponents

First and Second John characterize these opponents in several specific ways:

• They denied that Jesus was the Christ (1 John 2:22) — specifically denying that the human Jesus really was the Christ/Son (1 John 2:23; 4:15, 2 John 9)

• They denied that Christ had come in the flesh (1 John 4:2; 2 John 7)

• They claimed to be naturally without sin (1 John 1:6–10)

• Their conduct was haughty, loveless, and schismatic, which contradicted the gospel they claimed only they understood, causing others to question if they had the Spirit (1 John 2:26-27)

As Carson and Moo explain in their An Introduction to the New Testament:

“The differences between John's readers and John's opponents are substantial. The secessionists denied that Jesus was the Christ (2:22) — not apparently meaning that they disbelieved that Jesus was the Messiah of Old Testament expectation, but that the human Jesus really was the Christ, the Son (2:23; 4.15, 2 John 9). They denied that Christ had come in the flesh (4:2; 2 John 7). Judging even subject to sin: it did not inhere in their nature, display itself in their behavior, or hinder their fellowship with God. Meanwhile their own conduct was so haughty, loveless, and schismatic that they denied the very gospel they claimed that only they understood, prompting some of the more hesitant amongst those left behind to wonder at times if they had the Spirit at all (see 2:26-27).” (Carson & Moo 678)

Identifying John's Opponents

There are generally three overlapping options for identifying these opponents: proto-Gnostics, Docetists, or followers of Cerinthus. Given the timeframe of writing (late first century), it might be more accurate to say "proto-gnostic" rather than fully developed Gnosticism. But the essential point is that these groups existed early in Christianity, and John was likely writing against a nascent form of one or more of them.

While "Gnostic" encompasses a broad group, it generally refers to those who divided the God of the Old Testament from the God of the New Testament, and who saw the spiritual realm as superior to the material world. Docetists (from the Greek dokeo, "to seem" or "to appear") argued that Christ only seemed human but was not fully human in reality. Cerinthus advocated positions that combined elements of both.

The simplest explanation is that John was writing against people who would eventually become known as Gnostics and/or Docetists, with Cerinthus likely being a prominent figure within that movement.

The John-Cerinthus Connection

Early evidence from John's disciple Polycarp verifies that John himself had a direct conflict with Cerinthus. According to Irenaeus, who was himself Polycarp's student, John once encountered Cerinthus at a bathhouse in Ephesus:

"There are also those who heard from him [Polycarp] that John, the disciple of the Lord, going to bathe at Ephesus, and perceiving Cerinthus within, rushed out of the bath-house without bathing, exclaiming, 'Let us fly, lest even the bath-house fall down, because Cerinthus, the enemy of the truth, is within.'" (Against Heresies 3.3.4)

We can be reasonably confident in this account's reliability. Irenaeus notes that Polycarp "was not only instructed by apostles, and conversed with many who had seen Christ, but was also, by apostles in Asia, appointed bishop of the Church in Smyrna... [and] always taught the things which he had learned from the apostles, and which the Church has handed down, and which alone are true" (Against Heresies 3.3.4)

Interestingly, Polycarp seems to have adopted his mentor's passion for confronting heresy. During an encounter with the heretic Marcion, Irenaeus records: "And Polycarp himself replied to Marcion, who met him on one occasion, and said, 'Dost thou know me?' 'I do know thee, the first-born of Satan.'" (Against Heresies 3.3.4)

Cerinthus and John's Gospel

Irenaeus goes further, suggesting that John wrote his Gospel specifically to counter Cerinthus's heresy:

"John, the disciple of the Lord, preaches this faith, and seeks, by the proclamation of the Gospel, to remove that error which by Cerinthus had been disseminated among men... declaring that there is one Almighty God, who made all things by His Word, both visible and invisible; showing at the same time, that by the Word, through whom God made the world, He also bestowed salvation upon the men included in the creation." (Against Heresies 3.11.1)

If correct, this historical context helps explain why John emphasizes in his Gospel that "the Word became flesh" (John 1:14), directly contradicting Cerinthus's separation of the spiritual Christ from the fleshly Jesus.

What Did Cerinthus Believe?

According to Irenaeus, Cerinthus taught that:

1. The world was not made by the supreme God but by a lesser power

2. Jesus was not born of a virgin but was the natural son of Joseph and Mary

3. Christ descended upon the human Jesus at his baptism in the form of a dove

4. Christ departed from Jesus before the crucifixion, leaving the human Jesus to suffer alone

5. Christ could not suffer because he was a spiritual being (impassible)

Irenaeus explains:

"Cerinthus... represented Jesus as having not been born of a virgin, but as being the son of Joseph and Mary according to the ordinary course of human generation, while he nevertheless was more righteous, prudent, and wise than men generally. Moreover, after His baptism, Christ descended upon Him in the form of a dove from that Sovereignty which is above all things... But at the end, Christ again departed from Jesus, and that Jesus suffered and rose again, while Christ remained impassible, inasmuch as He was a spiritual being." (Against Heresies 1.26.1)

In this passage, note how Irenaeus specifies Cerinthus’s position as separating Christ from Jesus: “But at last Christ departed from Jesus, and that then Jesus suffered and rose again, while Christ remained impassible, inasmuch as he was a spiritual being.” Cerinthus evidently believed that Jesus was human (fleshly and passible) while Christ was spirit (spiritual and impassible).

This teaching contradicts John's polemical statements in his epistles:

• "Every spirit that confesses that Jesus Christ has come in the flesh is from God, and every spirit that does not confess Jesus is not from God. This is the spirit of the antichrist." (1 John 4:2-3)

• "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." (1 John 2:22-23)

• "For many deceivers have gone out into the world, those who do not confess the coming of Jesus Christ in the flesh. Such a one is the deceiver and the antichrist." (2 John 7)

Conclusion

While we cannot be absolutely certain that Cerinthus himself was the specific leader of the group John opposes in his epistles, the historical evidence strongly suggests that John was confronting beliefs very similar to those Cerinthus taught. The apostle's emphasis on Christ coming "in the flesh" and his insistence on the unity of Jesus and Christ directly addresses the kind of proto-gnostic, docetic teachings that Cerinthus and his followers promoted.

John's concern was not merely theological hair-splitting but addressed a fundamental question: Was Jesus Christ truly God incarnate who suffered for our sins in his flesh? For John, any teaching that separated the divine Christ from the human Jesus undermined the heart of the gospel and the reality of our salvation.