The passage
      v1-2. John, along with the other apostles, saw, touched and heard the divine "life." This "life" is present in God's revelation, in his Word, and was operative long before the creation of the universe. This Word became flesh in the birth of Jesus. So, the divine "life" was present in Jesus and in him they saw, touched and heard it. All who hear the Word (the gospel) and believe it, similarly possess the divine life - "eternal life."
      v3-4. John chooses to describe eternal life in the terms of fellowship with God. The same idea is found in Jesus' words recorded in John 17:3, "this is eternal life: that they my know you, the only true God, and Jesus Christ, whom you have sent." The word "fellowship" is best imaged in the intimacy of marriage, so "fellowship with the Father and his Son" involves a living and eternal union with God in Christ. This intimate union with the divine is also mutually shared between believers. The divine life makes us family.
      v5. John now defines the content of this revelation, or Word from God. Jesus is the source of this revelation, and belief in the Word produces eternal life. "God is light" is the revelation. He is the light in the sense of possessing pure life-giving knowledge. He is the source of pure truth, a truth in which error can have no place, Jn.8:12.
      v6-7. John next deals with three false claims made foolish by this truth ("God is light"), v6, v8 and v10. The point is simple enough, "if we claim" to be in fellowship with God then we will reject these three false claims.
      First, sin doesn't matter. The truth is that a person who is in fellowship with God, who is radiated by his light, will not "walk" in unrighteousness, Jn.3:19-21. That is, their life-style will not be oriented toward sinful living. Their relationship with Christ will produce a caring relationship with the brotherhood. John is not saying that a true believer will be free from sin. He is speaking about orientation, not failure. A believer is oriented toward the love of the brotherhood. To make this point clear, John goes on to speak of Christ's sacrifice working in the present to purify us from sin. When we walk in the light our constant failures are exposed and slowly, through faith in the inworking Spirit of Christ, we are oriented toward the care of others rather than self.
      v8. Second, the denial of our sinful nature. The truth is that a person who is in fellowship with God will recognize their sinfulness. When a person walks in the light their evil nature is exposed. A believer knows they are a sinner.
      v9. At this point John gives us a solution to the problems posed in the three false claims. We are all sinful, both in nature and deed. The way through this problem is by confession. This idea is dealt with differently by commentators on this passage. For some, it is either an ecclesiastical confession to a confessor priest, or a general confession said by members of a worshipping congregation. For others, it is the daily listing of our failings, both known and unknown. Yet, it is more likely that John is speaking about a recognition of the old Adam in us. As we walk by the light so we are reminded of whom we are; "my righteousness is but filthy rags", "all have sinned and fallen short of the glory of God." For John, confession is but a recognition that we stand at the foot of the cross, by grace through faith, and not of works lest anyone should boast.
      v10. Third, the denial of sinful behavior. A person who is in fellowship with God sees wrongdoing as evil. The light enables us to recognize immorality as immorality.

The light shines in the darkness
      C.S. Lewis described God as the "Transcendental Interferer." Our passage for study tells us something about the Transcendental Interferer and we, his many friends.
      First, verses 1-4 tell us about the Transcendental Interferer's person and the relationship that exists between him and his friends. We are in "fellowship" with him, says John. Life in all its fullness, or more rightly "eternal life", is a quality of existence which is best understood in the terms of the intimacy of marriage. The sensual bonding that exists between a male and a female, images the relationship that is possible between the believer and Christ. In Christian theology the title given to this doctrine is Mystical Union.
      Second, verses 5-10 identify three lies that must be rejected by his friends (v6, v8, v10). John tells us something of the quality of the Transcendental Interferer's person. He is "light", a radiance of perfection. It is because of this perfection that we cannot pretend to be in a relationship with Him while claiming that sin doesn't matter, or that we are free from sin, or even worse, that our evil behavior is not sinful. Sin does matter.
      Finally, the passage identifies a truth that must be believed. Gladly this truth is a very simple one, namely that we must constantly accept God's mercy for the limited person we are.

v2
      hJ zwh "the life" - "Life" as in "life force", "vitality", "existence." John plays with the ideas of life and light. Jesus, the Word, is like a light shining in the darkness of the world, and that light, the knowledge of God, gives life to those who come to it. John is saying that he and the other apostles have seen, heard and touched and have therefore come to know and so have been enlivened, and now they proclaim the gospel so that others may see the light and gain life.
      efanrwqh (fanerow) aor. pas. "appeared" - was made clear, made visible, manifested, revealed. marturoumen (marturew) pres. "testify" - we bear witness, we give testimony. The word has a legal background. The change in tense to present indicates the ongoing consequences of "we have seen", perfect tense. "We saw it and are giving our testimony", NJB.
      apaggellomen (apaggellw) pres. "we proclaim" - we announce, preach, proclaim, report. Used of the apostolic preaching, or better, the communication of the gospel, which witness is preserved for us in the New Testament.

v3
      koinwnia "fellowship" - partnership, sharing in, fellowship. The meaning here carries the sense of close intimate sharing/partnership both with God through Christ, and by extension, an intimate sharing/partnership with other believers.

v4
      tauta "this" - these things. Most likely the contents of the letter, but possibly the gospel
      hJmeiV "we" - Emphatic. When an apostle writes "we" he usually means "we apostles." Paul follows this practice, although on many occasions he means "we Jews."
      iJna + subj. "to [make] - in order that. Expressing purpose. "That our joy may be complete", Moffatt.
      hJ cara (a) "joy" - A sense of warm assurance in the love of God rather than a bubbly emotion.
      hJmwn "our [joy] - There is some manuscript evidence for "your" and this would certainly fit with the context.
      peplhrwmenh (plhrow) perf. pas. part. "complete" - may be made full, filled up, given fullness, completeness. "Full" is probably the best meaning; "a joy that is full and overflowing."

v5
      hJ aggelia (a) "the message" - message, report. "The gospel"
      oJti "-" - that. Introducing the content of the message.
      fwV "light" - As above, light is revelation, and God's revelation in Christ gives life. "God is light and doesn't have any darkness in him", CEV.
      skotia (a) "darkness" - God is pure and holy and so there is no darkness/untruth in Him.

v6
      ean "if" - Conditional clause, 3rd class, where the condition in the protasis has a probability of being realized. There are five conditional clauses through to v10. The negative clauses are best translated as representing false claims; "it is not possible to claim to be in fellowship with the Lord and at the same time knowingly and defiantly live a life marked by unrighteousness as if sin doesn't matter."
      eipwmen (legw) aor. subj. "claim" - say. "If some among you say", TH.
      peripatwmen (peripatew) pres. subj. "walk" - walk about. With reference to lifestyle; "conduct one's life", "live".
      yeudomeqa (yeudomai) pres. "we lie" - we lie. "Live a lie"
      ou poioumen (poiew) pres. "do not live - are not doing, making. By extension "practice." Here "not doing the truth." The context may give us a hint to the particular elements of God's will that John has in mind. v7 refers to "fellowship with one another" and so the sin may be a defiant disregard for the needs of our brothers and sisters. There is also a hint in the claim for a right standing with God that ignores right behavior. This possibly implies a reduction in the demands of the law. Therefore, the sin may be legalism, piety, where the law's demands are reduced so as to claim a state of obedience before God. "We do not put the truth into practice."
      thn alhqeian (a) acc. "by the truth" - [are not practicing] the truth. Possibly the truth of the gospel, but more likely God's standard of behavior. Possibly better generalized in a positive statement; "our words and our lives are a lie", REB, cf. Barclay.

v7
      en tw/ fwti peripatwmen "walk in the light" - "Walking in the light is the conscious and sustained endeavor to live a life of conformity with the revelation of God who is light, especially as that revelation has been made finally and completely in Jesus Christ. And this is the necessary condition of fellowship", Brooke.
      to aiJma (a) "the blood" - The redemptive sacrifice of Jesus
      kaqarizei (kaqarizw) pres. "cleanses" - purifies. The present tense indicates a continuous action. In Christ the stain of sin is removed, not just forgiven, "keeps on purifying us from all sin."

v8
      ouk ecomen (ecw) pres. "to be without [sin]" - [that] we do not have sin. The problem here is either legalism where the law is reduced so as to claim obedience, or perfectionism (full-surrender, second blessing, brokenness, release of the spirit...) where the sinful nature is denied.
      planwmen (planaw) pres. "we deceive" - we lead astray, deceive, mislead. Westcott claims the meaning of the word is "in all cases that of straying from the one way [James 5:19f]; not of misconception in itself, but of misconduct." A meaning of "deceive" seems best; "we live in a world of illusion", Phillips.

v9
      oJmologwmen (oJmologew) pres. subj. "we confess" - we confess, admit, acknowledge. To declare openly before God that we are in a state of rebellion against him, are in defiance of his will. "If we freely admit that we have sinned", Phillips.
      pistoV adj. "faithful" - reliable, faithufl. Brown says that the word here refers to the faithfulness of God to keep his promises, namely, to forgive those who call on him for mercy.
      iJna + subj. "-" - that. Here most likely introducing a consecutive clause, expressing consequence, result. The consequence of God's reliability and his justice is that he will keep his promise to forgive those who seek his mercy. "He is faithful and just, and as a consequence, will ...."