three New Testament writings, all composed sometime around AD 100 and traditionally attributed to John the Evangelist, son of Zebedee and disciple of Jesus. The author of the first letter is not identified, but the writer of the second and third calls himself “presbyter” (elder). Though the question of authorship has been much discussed, the language and contents of the three letters suggest a common source.

The first letter was apparently addressed to a group of churches where “false prophets,” denounced as Antichrist, denied the incarnation of Jesus and caused a secession so substantial that the orthodox remnant was sadly depleted. The faithful were deeply disturbed that the heresy found favour among pagans, and they apparently felt inferior because those who had left their midst claimed to have profound mystical experiences. The heretics asserted that they possessed perfection, were “born of God,” and were without sin. By placing themselves above the Commandments, they in fact sanctioned moral laxity. John's letter thus urges the Christian community to hold fast to what they had been taught and to repudiate heretical teachings. Christians are exhorted to persevere in leading a moral life, which meant imitating Christ by keeping the Commandments, especially that of loving one another. The spirit of the letter closely parallels that of the Fourth Gospel.

The second and third letters are closely akin to the first in language and ideas. The second exhorts a church, fancifully called “the elect lady and her children,” to boycott heretics who deny the reality of the incarnation. The third letter is addressed to a certain Gaius and complains that “Diotrephes, who lies to put himself first, does not acknowledge my authority”—a hint that Gnostic teachings were severely disrupting the community.