7Dear children, do not let anyone lead you astray. He who does what is right is righteous, just as he is righteous. 8He who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil’s work. 9No one who is born of God will continue to sin, because God’s seed remains in him; he cannot go on sinning, because he has been born of God. 10This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother.
This is a much bigger section, but I think it is warranted. The text is very clear cut here. Doing what is right is the mark of the righteous, and doing what is evil is the mark of the worldly. Though we are not defined by what we do, and we are not saved by what we do, what we do does demonstrate who we are inside.
It makes no sense for someone who is devoted to God to also be devoted to a sinful life. This is because we do not just believe that the Christian life is a choice, but that it is a choice that resulted in an internal change, and that internal change, here, is the implanting of God’s seed; rebirth. The whole point of Christ’s mission was to destroy the work of the devil, so how could the work of the devil persist in you if Chirst’s work is completed in you.
So look at your life. Is there sin? Is there righteousness? And sin here isn’t just the occational sin, or sins that you are combatting, but a life of sin. Is the sin in your life more precious to you than the righteousness of God? Do you look forward to Saturday night more than Sunday morning? For your life marks who your father is.