Sin is lawlessness (1 John 3:4), or transgression of the law of God (Romans 4:15), and literally means falling short of God's standard, not only in the outward conduct of the life, but also in the inward state and habit of the soul.
Sin of any kind is an offence against God and is subject to the penalty of spiritual death which is the severance of fellowship with Him, banishment from His presence, and eternal punishment in the lake of fire originally prepared for the devil and his angels (Matthew 25:41, 2 Thessalonians 1:9, Revelation 20:15).
Since Eden mankind can discern between good and evil, and so is conscious that sin is intrinsically vile and polluting, and that it justly deserves punishment. Sin results in guilt and pollution.
The spiritually blind have no sin (John 9:41) - like the mentally immature or handicapped - for God has manifested Himself to all men, but they chose for themselves gods of their own making (Romans 1:18-23). Rejection of the Lord Jesus is the ultimate sin, the sin against the Holy Spirit, for which there is no forgiveness, ever (Matthew 12:31, John 15:22, 24).
The presence of the truth, the Word of God, within the believer, brings to him a clearer and greater consciousness of sin in his nature (verse 1:8) and of sins in his life (verses 9, 10). If a person calling himself a Christian denies having any personal guilt or any conscience of sin, he deceives himself, and is opposing what is stated in the Word of God, as if God the Holy Spirit were a liar. He is even worse than being a liar: he does not have any truth in him at all.
The word confess is the translation of a Greek word meaning "to say the same thing" and is the opposite of denying. When in His Word He says that what we have done is sin, we are to acknowledge to Him that it was so. Repentance and a request for forgiveness are implied.
Confession is to make acknowledgement:
to God: of all sins against Him (Leviticus 16:21; Ezra 9:5-15; Daniel 9:3-12),
to a neighbour: of offences made to him (Matthew 18:15), and
to the local church: of misdeeds affecting the local body of believers (James 5:16).
Forgiveness of both sinful nature and committed sins is the peculiar prerogative of God (Psalm 130:4; Mark 2:5), for which He has shed the blood of Christ, now faithfully provided by Him to those who confess their sins (as we forgive those who have sought forgiveness from us - Matthew 18:35).
Sin interrupts, but confession restores fellowship with God, and immediate confession will keep the fellowship unbroken. All sins are forgiven freely (Acts 5:31; 13:38). By this act of grace we are for ever freed from the guilt and penalty of our sins.
We find a model confession in Psalm 51:
Honest admission of sin - verses 3 and 4.
Real sorrow over sin - verse 17.
The main characteristic of true confession is godly sorrow (2 Corinthians 7:10).
Supplication for forgiveness - verse 1 and 7 to 9.
Faith that God has heard and will restore fellowship - verses 12-15.
The affectionate words my little children are used, like the Lord did to His disciples during His last Passover supper (John 13:33). They probably should be translated here as my little born ones or, better still, my little born-again ones.
Those who walk in the light are cleansed from all sin by the blood of Jesus Christ the Son of God (1:7); this letter, like all the Word of God, is written so that by walking in obedience to it, we may please God by not sinning.
No one can truthfully claim sinless perfection, for the presence of sin is all around us in this world and we are bound to be occasionally tainted with it, no matter how hard we strive to keep away. God, in his mercy, has provided for this: if any one commit sin, we have an Advocate with the Father, Jesus Christ the righteous. Note that:
He isn't called here by the impersonal name God, because He is still our Father, even though we have sinned. Our salvation rests upon what Christ has done for us, and that is a finished work and nothing is to be added, for He has done all we need for salvation.
it is not written that if anyone repents, nor if anyone confesses his sins, neither does it say that if anyone goes through a ceremony to get rid of his sins. Before we even repent of that cruel or brutal word we said, the very moment we had that evil thought, and the moment we did that wrong act, Jesus Christ was there at the throne of God to represent us as Satan was there accusing us.
Advocacy is that work of our Saviour for sinning saints which He carries on with the Father whereby, because of the eternal efficacy of His own sacrifice, He washes their sins away. The blood of Christ answers forever to all the law could say as to their guilt, but they need constant cleansing from the defilement of sin, through the water of the word of God (Ephesians 5:25-27) and the intermediation of Christ in heaven: as righteous, He is qualified to plead their case and to enter the Father's presence (Hebrews 2:18).
The Lord Jesus, as both priest and sacrifice (Hebrews 9:14), is himself the means of propitiation (payment) for our sins, and, indeed, for the sins of the whole world (Hebrews 2:9) if they will only be reconciled with God (2 Corinthians 5:19-21).
There is at the present time, a legion of people who call themselves Christians, and even deceive themselves into thinking that they know Him, vastly more so than in John's time. They are only genuine if they pass the test of keeping His commandments. He who calls himself a Christian but does not keep His commandments is a liar and the truth is not in him (like he who says he has no sin).
Commandments is used here in two senses:
in the general sense of the divine will, however revealed, "His word" (2:5: Matthew 5:19-20, 15:8-9, 19:17-19, 22:37-40, John 14:15, Galatians 6:2); and
especially of the "new commandment" of Christ, a reiteration of the "old", yet stronger (John 15:10-12): that His disciples should love one another with the love He evidenced for us, to the point of going to death in our place.
It has nothing to do with keeping the traditions, rites or "sacraments" introduced by popes and others. The Lord quoted Isaiah, saying: "… in vain they worship Me, teaching as doctrines the commandments of men" and added "… for laying aside the commandment of God, you hold the tradition of men … you reject the commandment of God, that you may keep your tradition" (Mark 7:8-9).
The apostles have given details of Christ's commandments in writing for us (1 Thessalonians 4:2). In 1 Thessalonians 5 there are more than twenty. These are just some of the commandments which the Lord Jesus has given to believers, and if we are to have fellowship with the Father and enjoy it by having assurance in our own hearts, we must keep them.
We must not feel that we are free to do as we please. The legitimate Christian doesn't do as he pleases, but he does as Christ pleases, just as He obeyed the Father's commandments (John 15:10). Obedience to Christ is essential and is the very basis of assurance of salvation, just as disobedience to Christ is evidence of not knowing Him. Church members who have no love for the Word of God and are disobedient to Christ cannot really be His children. They have never been regenerated.
Chapter 1
8 If we say we have no sin, we deceive ourselves, and the truth is not in us.
9 If we confess our sins, he is faithful and just, and will forgive our sins and cleanse us from all unrighteousness.
10 If we say we have not sinned, we make him a liar, and his word is not in us.
Chapter 2
1 My little children, I am writing this to you so that you may not sin; but if any one does sin, we have an advocate with the Father, Jesus Christ the righteous;
2 and he is the expiation for our sins, and not for ours only but also for the sins of the whole world.
3 And by this we may be sure that we know him, if we keep his commandments.
4 He who says "I know him" but disobeys his commandments is a liar, and the truth is not in him;
5 but whoever keeps his word, in him truly love for God is perfected. By this we may be sure that we are in him:
6 he who says he abides in him ought to walk in the same way in which he walked.
7 Beloved, I am writing you no new commandment, but an old commandment which you had from the beginning; the old commandment is the word which you have heard.
8 Yet I am writing you a new commandment, which is true in him and in you, because the darkness is passing away and the true light is already shining.
9 He who says he is in the light and hates his brother is in the darkness still.
10 He who loves his brother abides in the light, and in it there is no cause for stumbling.
11 But he who hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes.