The First Epistle General of John is actually more like a sermon than a letter. It lacks the usual greetings, thanksgiving, and closing greetings (or blessing) that are standard features of letters in the Greco-Roman world and in the several examples of letters that are now part of the New Testament. First John seeks to warn its readers against false teachings and to encourage them to live according to the true faith which they received from the apostles. The readers are told that certain opponents of Christ (KJV, “antichrists”) have left the true faith (2.18,19), but they still perpetuate their false teachings and deny that Jesus is the Christ (2.22). This type of false teaching typically viewed the human body and the physical world as evil, so that salvation essentially meant becoming free from the body and the world, and even from moral responsibilities or compassionate caring for the poor. Such “antichrists” even denied that Jesus really had a human body (4.1-3). But, this letter says, echoing the Gospel according to John, true Christians will strive to live in the light and love one another (1.7; 2.8-11; cf. John 3.19-21). They will affirm Jesus as the Christ. And because they know that God is love, the faithful will love one another and care for one another (3.11-18). It is Christ who is the model for this self-giving love (3.16), and it was Christ's singular commandment to his followers that they love one another (John 15.12). Right conduct of life flows from right faith and teachings. Ancient tradition ascribes the three Epistles of John to the writer of the fourth Gospel, and the many thematic and verbal affinities with that Gospel support that conclusion.
Living in the Light (1.1—2.17)
Children of God and Children of the Devil (2.18—3.10)
The Love that Comes from God (3.11—4.21)
Faith's Victory: Whoever Has the Son Has Eternal Life (5.1-21)