Sin and the Assurance of Faith.

The main purpose of the Epistle of First John is to assure believers of their salvation in Jesus Christ. Throughout the Epistle, John presents several truths that characterize
genuine faith, allowing the reader to know where they stand concerning saving faith. One of the main tests of the genuineness of our faith lies in the way in which we deal with our sins.

In 1 John 2:1-2, John speaks about the holy calling of a believer and reminds us specifically of how and why we are to be separate from sin. In v.2 we are told that Jesus Christ is the propitiation for our sins, which essentially refers to the fact that Jesus Christ's
substitutionary death on the cross, was the appeasement or satisfaction for God's holy wrath against sin. It was here on the cross that Jesus paid our sin debt of death and
judgment, thereby enabling us to be completely forgiven for all of our sins (1 John 2:12).

Now having had our sins forgiven and the righteousness of Christ imputed to us, we are reconciled to God (2 Cor 5:21). We now walk in newness of life, having been given new
affections and desires with regards to the things of God. Instead of living in sin, we recoil from it. Instead of having no guilt or shame over sin, we are now grieved when we sin.
To be clear, we can never undo the forgiveness of sins and the perfect righteousness of Christ that have been applied to us, yet we do strain our relationship with our Saviour when we sin. This is true in any family relationship. Sin in the present dramatically impacts our daily relationship with christ.

1 John 2:1 says, "My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an Advocate with the Father, Jesus Christ the Righteous."  1 John assumes the obvious. We will as redeemed people, still sin.
However, along with what has already been said above, we are told that our day-to-day sins are forgiven, because Jesus Christ our Advocate, represents us to the Father.
The main idea here concerns the certainty behind our confession of sin being accepted. The daily sins that the redeemed commit were ultimately paid for by Jesus Christ on the cross of Calvary. Therefore, when Christ appeals to His Father regarding the sins that we have just committed and confessed, He does so as the One who has previously paid for that sin in full with His blood.

Inherent within the instruction about believers confessing and forsaking sin is a crowning proof that one is saved ( 1 John 3:2). Through the New Birth, we now possess a
new nature which causes us to loathe the sin that we commit and long to be immediately pardoned. This response to one's sin is unique to the believer. Those who refuse to
confess their sin, also at the same time do not actually agree with God's assessment of it.

1 John 1:8-9 says,
                     "If we say we have no sin, we deceive ourselves, and the truth is not in us.
If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness."

Herein lies the evidence of salvation. Believers, though not enslaved to sin, will still sin. That they confess sin, loathe it and seek to turn from it, proves that they are indeed God's children ( 1 John 3:9). An unbeliever, on the other hand, refuses to agree with God about his sin; and won't confess it, thereby proving that the truth is not in him.

1 John 3:8-9 states that,
                  "Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil. No one born of God makes a practice of sinning, for God's seed abides in him; and he cannot keep on sinning, because he has been born of God."

We are told that those who are truly God's, cannot keep on sinning. The reason given is that God's seed abides in us. As new creations in Christ, we are spiritually alive and are permanently indwelt by the Holy Spirit. Our new nature and the Spirit's presence prevent us from continually living in sin. Verse 10 ends the comparison with a concluding principle.

                " By this it is evident who are the children of God, and who are the children of the devil: whoever does not practice righteousness is not of God, nor is the one who does not love his brother."

Determining whose child you truly are, can be found by what you do with sin.
Be encouraged and assured of the validity of your faith, when you see a wrestling and striving for holiness, coupled with a desire to confess sin when it occurs. By contrast, one should be greatly concerned about their eternal destiny when their life is characterized by continually living in sin, with no guilt, confession of sin and repentance. This is the mark of the unbeliever.

May we live a life of repentance, obedience and faith!