A. Belief in Jesus as the Christ is victory (5:1–3). 5:1. Just as the Gospel of John is written in order that hearers and readers might believe that Jesus is the Christ, the Son of God, and in believing have life in his name (Jn 20:31), the promise of this message concludes the final chapter of the first Johannine Epistle. To believe that “Jesus is the Christ” implies the content of Christian faith, but the loving regard for his followers is again declared as its authentic measure. Especially as an antidote to Christians who might yet be tempted to abandon the community and their belief in Jesus, the elder emphasizes that believing “Jesus is the Christ” is the center of spiritual birth.
5:2–3. For those refusing to risk synagogue expulsion (Jn 9:22; 12:42; 16:2) by confessing belief in Jesus’s messiahship openly, this reminder was a targeted appeal to bolster their courage. And, in contrast to the first antichrists, who split off from the church and denied their fellowship with brothers and sisters in Christ, obeying God’s commandments and abiding in his love is measured by love for one another. The implied meaning here is for corporate solidarity with Christ and his community. Thus, Christian faith is the victory that overcomes the world and all of its temptations (5:4).
B. The life-producing testimony (5:4–12). 5:4–9. To believe in Jesus as the Christ is also to believe in him as the Son of God (Jn 20:31), and Gentile believers are thus included in the confessional formula, as well as Jewish believers. Not only is it the Christian faith that overcomes the world (5:4), but so do the Christian faithful (5:5) by their trust and obedience. Jesus’s coming by water and by blood (5:6a) likely refers to one or more of the following: the physical birth process emphasizing Jesus’s humanity, martyrological associations with the sacramental themes of baptism and communion, or the water and blood that flowed from the side of Jesus in Jn 19:34. Whatever the case, the emphasis is on the suffering humanity of Jesus and its implications for discipleship: if Jesus indeed suffered and died, we must be willing to do the same (Jn 6:27, 51–58, 63). To this emphasis is added testimony of the Spirit (5:6b), and these three testify to Jesus’s authenticity as the Son of God (5:7–8). As the Johannine Jesus emphasizes three witnesses, not just his own (Jn 5:31–38; 8:13–19; Dt 17:6; 19:15), so the Johannine elder emphasizes three witnesses—the water, the blood, and the Spirit—which bear final testimony in the hearts of believers (5:10). These are ultimately the testimony of God (5:9), which outweighs human testimony on all accounts.
5:10–12. Parallel to those who “make [God] a liar” in 1:8–10 by denying one’s sin, one here makes God a liar by not receiving God’s testimony about Jesus’s fleshly humanity (5:10). If claiming to be without sin is a matter of arguing that cultural and religious assimilation (participating in pagan festivals, worshiping Caesar, etc.) are not sinful, these liberties were likely challenged by the docetic teaching that Jesus was so divine that he could not have suffered and died. Therefore, one cannot expect believers to risk suffering and loss; if Jesus did not suffer, we need not do so either. Just as hope for the resurrection can only come by means of the cross, the only way to life is through the dead and risen Son of God (5:12).
C. The boldness of faith (5:13–15). Again the elder declares his purpose in writing (see 2:14, 21, 26), and this time he explicitly echoes the evangelistic purpose of the Fourth Gospel (Jn 20:31): that his hearers/readers might believe in the name of the Son of God and thereby know that they have eternal life (5:13). The elder then reminds them of the promise of Jesus that anything asked in his name will be granted by the Father (Jn 14:13–14; 15:16) and that by asking in his name, the world is overcome (Jn 16:23–32) (5:14–15). Just as the purpose of Jesus is to further the will of the Father who sent him (Jn 4:34; 5:30; 6:40), the purpose of his followers should be the furthering of his will in the world (Jn 15:14–15) as his partners and friends.
D. Keep from mortal sins—in particular, idols! (5:16–21). 5:16–17. This section picks up again the main topic outlined in the opening chapter (1:5–10): sin—its identification and its consequences. Here the elder distinguishes between mortal sins (leading to death) and venial ones (not leading to death) (5:16). The practical importance of the distinction involves prayerful graciousness and discernment regarding some sins but the stern rejection of death-producing ones.
5:18–20. Therefore, the one who is truly begotten of God does not sin, and he or she is protected by the Only Begotten Son of God (Jn 1:14, 18), who has overcome the evil one (5:18). The elder thus concludes his letter with three corporate affirmations of what “we know” as bases for Christian faith and practice.
5:21. On one hand, the last verse seems out of place. What if, however, it is added as a crystallization of the central spiritual and moral thrust of the entire epistle? To commit oneself to Christ as the Only Begotten Son of the living God is to deny and disavow all idolatries and their associated practices, including pagan worship and its festivals. There is one Lord—Christ Jesus—and just as he laid down his life for his friends, so should his followers be willing to do on behalf of others. So staying away from idols becomes a leading measure of one’s love for Christ and for one another.