If we claim to be without sin, we deceive ourselves and the truth is not in us. If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness. If we claim we have not sinned, we make him out to be a liar and his word is not in us.
Romans 7 is the classic go-to passage to talk about indwelling sin (see also Romans 6 and 8). When I say indwelling sin, I’m using a theological description to simply talk about either sin residing in us, or our propensity to sin. It seems to me that the main point in that controverted passage is that apart from the Spirit, humankind resides in the flesh, which often in Scripture doesn’t just mean our body, or physical being, but refers to us in our fallenness or brokenness.
Regardless of how we parse all of that, or the passage above from 1 John, I think it’s indisputable that if we don’t live by the Spirit, we’ll live by the flesh, just as Galatians 5 tells us. And we might say the reason for that is indwelling sin.
I think it’s healthy to recognize and acknowledge that. Instead of rationalizing and excusing our attitudes and actions, or wondering what’s wrong with others, we need to chalk it down to one thing: sin, and indwelling sin. We struggle with sin in the life, and that’s simply a matter of fact. And we do sin; there’s no such thing as sinless perfection here and now.
But God not only forgives us as we acknowledge our sins, but also cleanses us from all unrighteousness. In other words, there’s a way to deal with it through the gospel, through Christ. But it’s not by sweeping it under the rug, or pretending it doesn’t exist. We’re not at all defined by sin; we’re “in Christ.” But we need to hold on day after day to the truth and power of the gospel for us.
God is faithful, and will help us through all of this. In and through Jesus.