1 John 3:4-10 are among the more difficult in the Bible and can cause many Christians to doubt their salvation. Why? Because it seems to be saying that those who sin are not truly Christians.
That is clearly not what John means, however, as we’ve seen in 1 John 1:8-10 and 2:1.
So what does he mean?
I think we see a hint of the answer in 1 John 1:6-7.
True children of God walk in his light, not in darkness. Why?
Because they love God. They believe he is good. And they strive to be like their Heavenly Father.
People living in darkness are not this way. Instead, they have deep-seeded doubts about God, questioning the goodness of his character and his commands. And they essentially say, “If that’s the way you really are, if that’s the way you really think, I want nothing to do with you.”
That was Satan’s attitude.
That was the attitude he passed on to humanity in the garden.
And that’s how many people live today.
Such people have not seen or known Jesus or his Father.
True Christians don’t live that way. They can’t live that way.
Though they may fall into sin, when God’s light exposes it, they repent. No excuses. No trying to justify their sins. And certainly no questioning of his goodness.
The question, then, is not whether you sin or not. All of us sin. The question is if you’re walking in the light or not.
Because if we walk in the light as he is in the light, confessing our sins and repenting of them, the blood of Jesus his Son purifies us from all sin. (I John 1:7)
And the good news is, when our hearts condemn us for our failings, God is greater than our hearts and knows all things. He knows we truly love him and desire to please him. And he accepts us. (1 John 3:20)
So let us rejoice in his grace, singing with John.
See what great love the Father has given us that we should be called God’s children—and we are! (1 John 3:1)
Moment to Moment (Bible blog) 