There is no doubt that the author of the three short letters at the end of the New Testament bearing the name of John is the same as the author of the Gospel of John. He is the son of Zebedee and one of Jesus’ twelve apostles. Very likely these letters were written much later than the Gospel, for they do not address the problem of conflict with the Jews, which is a major topic in the Gospel account. The suggestion is that by the time the letters were written, the Christians had separated themselves from the Jewish community and were maintaining an identity of their own. They do address problems of false teachers, as we see in the first and second letters, and of dissension in the church, the third letter.

The purpose of the first letter, by far the longest of the three, is to provide believers with the assurance of eternal life. One obstacle to that assurance was the teaching of heretics whom John addresses as having the spirit of antichrist. Perhaps they were Docetists, an early form of Gnosticism. Gnostics generally believed that salvation was attained by knowledge, and Docetists advanced the "knowledge" that Jesus didn’t really come in the flesh, that the incarnation was only an appearance. Docetism derives from the Greek word dokeo which means "to seem." Such a view would undermine the atonement, for then man, who was guilty of sin before God, could not die for that sin. The mediator must be true man and true God at the same time in order to finish the work of atonement.

In contrast to the sham of a doctrine that substitutes appearance for reality, John offers the historical fact of Jesus the man dying for our sin and becoming an effectual atoning sacrifice. With our sins washed away by his blood, we can now stand before the God who is pure Light.

But how do we know that we personally are saved? As we sing in the song, "Is it for me, dear Savior?" How can I be sure that I have eternal life, and that I have been truly washed by the saving blood of Christ? John offers the proof of the new birth, that which Jesus announced to Nicodemus and about which John wrote in his Gospel. If we believe that Jesus is the Christ, then we know that we have been born of God (5:1). Those born of God have been brought to that new birth by the Holy Spirit, and John mentions three times that we may know that we know Him by the presence of the Spirit in our lives (2:20, 3:24, 4:13). The Spirit’s influence is felt by changes in our lives. Although John does not use the term "fruit of the Spirit" as Paul does (Gal. 5:22), what he is listing are indeed the fruition of the Spirit’s indwelling presence. For instance, John writes that we can be assured by the fact that we keep his commandments (2:3, 2:29, 3:3, 3:21). He does not mean that we keep them so perfectly that we no longer sin, for he states emphatically that if anyone claims that he does not sin, he deceives himself and the truth is not in him (1:8-10). But a pattern of obedience, perseverance and not loving the world (2:15) is proof of our being begotten by God. Also offered as proof of our new birth is the fact of our loving our brothers (3:14, 3:19, 4:7-8, 12). Everything in the letter points to reality rather than mere appearance.

When we have assurance of our regeneration, our new birth, and thus of our eternal life (5:13), we can have assurance in prayer (5:14), and in knowing that God will keep us safe from the evil one (5:18) and from continuance in sin (3:9), that he has given us an understanding (5:20), and that we truly are children of God (3:1)! How we need this assurance!