Verses 18 – 21: Faith Provides Understanding
“18 We know that everyone who has been born of God does not keep on sinning, but he who was born of God protects him, and the evil one does not touch him.
19 We know that we are from God, and the whole world lies in the power of the evil one.
20 And we know that the Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, in his Son Jesus Christ. He is the true God and eternal life. 21 Little children, keep yourselves from idols” (v. 18-21 ESV).
John transitions from faith providing confidence and faith enabling prayer into bold statements of fact. Three of the final four verse of 1 John 5 begin with the statement “we know”. As previously discussed, oἴδαμεν is article of οἶδα, which means “to know”, and also translates experience, learn, know how; be acquainted with, recognize, acknowledge; remember; and pay proper respect to. Faith provides understanding to the believer that unbelievers simply do not possess. In verse 18, John again returns to an earlier point he made in this epistle that those who are born of God do not continue to sin (cf. 3:6, 9). John’s use of the perfect participle γεγεννημένος here discussing those “born of God” suggests a permanent relationship begun sometime in the past that has continuing results from this new birth experience.
It is quite reasonable to assume that the person truly born again is given the ability to avoid falling into habitual sin. This might seem to contradict verses 16 – 17 but this is not the case. John stated that if a Christian sins his brother will intercede for him yet here says that Christians do not sin. Habitual sin is not the normal state of the believer; rather, resistance to sin is to be expected of all believers. Where there is habitual sin, there is likely unbelief to be found as well. In the second half of verse 18, the evil one does not touch the believer because of some protection. Here John does not specifically state who is protecting the believer. However, from earlier in the epistle, believers are assured that God is within them and is greater than he who is in the world (cf. 4:4). It is Jesus Christ who protects Christians.
Faith provides understanding of the true nature of the natural world. While John audience is assured in verse 19 that they are indeed from God, he also provided a very vivid reminder that the world lies in the power of the evil one. The King James Version translates this verse to say the whole world lies in wickedness. The simple point John is making is that the world is under the control of Satan yet his audience belongs to God and are safe from Satan. There is an important point John makes here that is easy to miss. A person is either a child of God’s or belongs to the world. John does not leave room for people to choose a neutral position. There is a clear implication here: if one does not belong to God and belongs to the world then by default that person belongs to Satan.
The third of the “we know” statements from John in these closing verses states what John has been an eye witness to which is Jesus Christ has come. This affirmation of the incarnation is important. First, it states the knowledge of what John experienced and that his audience knows from John’s telling. Second, recall John is writing against false teaching. Those false teachers questioned the deity and humanity of Christ and believed all matter was evil. An incarnate Christ posed a real problem for these false teachers. Jesus is clearly not one of these false teachers. Rather, He provides the needed understanding about His deity.
John explains to his audience that believers know him who is true and they are “in him” using ἐν τῷ with the implied meaning of being in union with Jesus Christ though this may also refer to being in union with God the Father (cf. John 17:3). The latter is the position taken by Utley though for this writer it seems more likely the union implied is with Jesus Christ. It is through this union that communion with the Father is made possible. Regardless, the point is well taken that believers are in the true God and as such have eternal life.
John’s final verse again uses the term of endearment “little children” (cf. 2:12, 28; 3:7, 18; 4:4). Again, John is writing to believers for whom he cares deeply and he is also writing as an elder statesman of the church. John goes on to tell them to keep themselves from idols though the word here translated “keep” (φυλάξατε) might better be translated as “guard” yourselves from the idols. The question is this: to which idols does John refer? While anything that replaces God can be construed as an idol, it is unlikely that is the meaning John intended.
Ephesus is the “temple-keeper of the great Artemis” from Acts 19:35 and it is possible that is the meaning John intended here. Being constantly surrounded by the idolatry from which many likely converted, it would make sense for John to warn these believers not to return to idol worship. However, in the context of the entire epistle, it is equally likely that John intends to warn his readers about following the false teaching of those who had departed and whose influence could still be felt in their congregation. Regardless of precisely which meaning John intends, it is clear that believers are to maintain the focus on truth and reject the false that is found all around.
 Newman, Barclay Moon. A Concise Greek-English Dictionary of the New Testament. (Stuttgart, Germany: Deutsche Bibelgesellschaft; United Bible Societies, 1993), 123.
 Akin, Daniel L. The New American Commentary, Volume 38 1, 2, 3 John, electronic ed, Logos Library System. (Nashville, TN: Broadman & Holman Publishers, 2001), 211-12.
 Plummer, A. The Epistles of S. John, With Notes, Introduction, and Appendices, The Cambridge Bible for Schools and Colleges. (Cambridge: Cambridge University Press, 1896), 169.
 Utley, Dr. Robert James. The Beloved Disciple's Memoirs and Letters: The Gospel of John, I, II, and III John, Study Guide Commentary Series Volume 4. (Marshall, TX: Bible Lessons International, 1999), 243.