Fruit Inspection 2.

1 John 3:6 No one who abides in him keeps on sinning; no one who keeps on sinning has either seen him or known him.7 Little children, let no one deceive you. Whoever practices righteousness is righteous, as he is righteous. 8 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. 9 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. 10 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. ESV

Many times the above section of scripture is used for judging another person or oneself is in the faith or not. From the initial appearance it does seem to be a proving text for settling the question. This however, comes from a not making the distinction between law and Gospel. To make this clearer one needs to use the context in which this passage is placed.
The nearer context is backing up to the first verses in the chapter:

1 John 1:1 See what kind of love the Father has given to us, that we should be called children of God; and so we are. The reason why the world does not know us is that it did not know him. 2 Beloved, we are God's children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is. 3 And everyone who thus hopes in him purifies himself as he is pure. ESV

God the Father has called us his children. It is by His pronouncement that we know this. The difficulty presents itself when we see sin in our lives and in the lives of our brothers and sisters. The statement is often made that we and should know better than to act a certain way or to serve our neighbour more fully. When one keeps on reading it shows that we are children of God now not in the sometime future when we have personally resisted all temptation. This promise is to be looked at for the assurance not what we see with our own eyes. The further promise is that it will appear what we will become. This refers to the time after we depart this veil of tears and trouble. These promises also serve as a motivation to resist temptation when we see it coming and serve those in need when we see it. This is done throughout our daily rounds in our vocations as family member, employee, employer and citizen.

If a person finds him or herself not loving another brother or sister as earlier in the letter confess his or her sin and God will cleanse of all unrighteousness. The law always accuses and never gives strength to overcome sin. In this way the law serves the Gospel by pointing us back to our Triune God. So where would one find this strength?

1 John 4:7 Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. 8 Anyone who does not love does not know God, because God is love. 9 In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him. 10 In this is love, not that we have loved God but that he loved us and sent his Son to be the propitiation for our sins. 11 Beloved, if God so loved us, we also ought to love one another. 12 No one has ever seen God; if we love one another, God abides in us and his love is perfected in us. 13 By this we know that we abide in him and he in us, because he has given us of his Spirit. ESV

What we need to hear again and again is how we are loved by God. How that this love was such that He sent His son into the world so that we may live through Him. God loved us first, dwells in us by his Spirit so that we love one another. This again is the fruit of the cross of Christ and not something we muscle up from within ourselves. We receive this fruit at our baptism when we are born of water and Spirit. Again all glory to God alone.

In the Name of Jesus. Amen. †