There has been much said about the letter of 1 John and the selected passage of 1:1-10, but how would a Christian today apply this timeless message? One way is to realize that the antichrist is more than something that comes out of the book of Revelation. The letter says tat any antichrists have already come (see 1 John 2:18), but they are the ones who deny that Jesus came in the flesh. There are many false versions of Jesus that are floating around today. There is the idea of the Latter-Day saints that say that Jesus is a separate god from the Father. This is a Jesus that cannot save because it is one that is contrary to scripture. The passage discussed says that Jesus is able to forgive sins and He can do it because He is God in the flesh. Anything else denies the incarnation which is central to the Christian faith.
This passage is also contrary to the rampant universalism that seems to have infiltrated certain parts of the church. Only those who repent and believe in Jesus, that He came in the flesh, and believe His divinity will be saved. All others are antichrists and will be lost. Therefore, it is imperative that we as Christians evangelize and teach proper doctrine. We need to teach the same Jesus that john waled with, listened to, and touched so people will be saved.
Another thing that is important in this passage is the issue of sin. This issue is important not only in this passage, but in the rest of the letter. We simply cannot be in fellowship with God and be living lives of rampant sin at the same time[1]. Either we are walking in the light of Christ, or we are not. This is a hard message for some to come to terms with because we are afraid of change. We like to hold on to what is familiar, even if it is something harmful. Make no mistake, this does not mean that when we come to faith that we stop sinning and become sinless.
The Lord Jesus never promised us, nor said and such thing. To be clear, we will sin as it is in our nature. However, if we confess that sin we are forgiven. No strings attached and there is nothing we need to do work wise to make that happen. Sinning and living in sin are two different things, and it is something that we need to understand. Are we waking up on a daily basis with the goal of serving Christ, and relying on His grace and mercy at all times? If that is the case, then your mind is on the Lord, and you are not living in sin. Sin is not your priority in life, but the Lord is.
If you are following the will of God, then you are a follower of Christ and you are walking in the light. Walking in the light does not mean that we will not sin. John makes that clear and he says that if deny that fact then we are liars[2]. Through that constant forgiveness that we seek through Christ we are still in fellowship with Christ even though we fail. That is assurance in faith. Praise be to God!
[1]. Campbell and McKnight, 1, 2, And, 37.
[2]. Campbell and McKnight, 1, 2, And, 37.