THE PRACTICAL EVIDENCE OF SALVATION.
1 John 3:7-10.
I like the familiar touch of John, who refers to his congregation as little children in danger of being led astray (1 JOHN 3:7).
A tree is known by its fruit (cf. Matthew 12:33). The apostle speaks first of the practise of righteousness, which proves our righteousness and our identification with the righteousness of Christ (1 JOHN 3:7); then of the habitual sinfulness of the sinner, who is identified thereby with the devil (1 JOHN 3:8). The devil's habit has been to sin from the very beginning, but the Son of God came to destroy the works of the devil.
John moves immediately from the eternal Son of God to the begotten-ness of Christians (1 JOHN 3:9). If we are begotten of God we will not blatantly and habitually sin. His seed within us can only bring forth good fruit (cf. Matthew 7:18). In fact, we are unable to continue in the practise of sin exactly because we have been begotten of God.
Ultimately our respective attitudes to sin and righteousness separate the saints from the sinners (1 JOHN 3:10).
The chapter began with the love of God, which named us as the sons of God. One of the fruits of our son-ship, and of having the righteousness of Christ, is our love towards the brethren (1 JOHN 3:10).