Galatians 5:11 talks about "the scandal of the Cross." The Cross of Christ is offensive for many reasons, not least is the shame crucifixion carried in the ancient world. The Son of God put to open shame is offensive, scandalizing.
Galatians 6:12–14 sheds some light on another sense of scandal. It is the natural desire of all of us to "boast in [our] flesh," and the Cross of Christ attacks that at its root. "[F]ar be it from me to boast save in the cross of our Lord Jesus Christ," stands in contrast to boasting in the flesh. The latter attempts to find something in ourselves for God, the former sees that Christ is our only righteousness.
That's worth meditation. It's far easier for fallen men and women to say "Christ is my righteousness" than it is for us to say "Christ is my only righteousness." The first leaves a small opening for us to add our own righteousnesses to Him. The second is an acknowledgement that nothing I can do, and nothing in me, can add anything to what Christ has done for me. His death is my only hope for salvation before God, and there is nothing I can do that can add to that.
As far as I know, every Protestant claims to condemn the idea of an act of supererogation. But that idea seems to lurk just below the surface in our hearts. We all secretly cherish the belief that there's something we can do that will just sort of round out the righteousness of God by faith (Romans 3:21–22).
We can't quite accept that God justifies the one who does not work, but believes (Romans 4:5). We all want to add some sort of qualifier to that statement. And we betray ourselves when we act as a sort of gatekeeper of salvation: when we say something like, "I just don't see that he can be saved and act like that."
What we're really saying is, "I wouldn't ever do that!" It's the same thing the Pharisees did (Luke 18:9).
As far as I can tell, "God be merciful to me, a sinner!" (Luke 18:9–14) is one prayer He always answers (Romans 10:8–13).
Still, there is the question of how we should think about someone who makes some sort of profession of faith and yet appears to live in sin. The Pharisaic approach is clearly wrong, but there is some Scriptural support for the notion that a life of continued sin indicates a lack of new birth. On the other hand, Scripture contemplates a true believer who doesn't act like one. We should consider both of these.
1 John 3:8–10 is one of the tests Scripture gives: whoever has been born of God does not practice sin. Well, that seems pretty straightforward, but it raises some questions. Is sinning the same thing as practicing sin? In other words, does this mean that anyone who sins is not born of God? Or does it mean something like, anyone who sins deliberately is not born of God? Or does it mean something like, anyone who lives in long-term, unrepentant sin is not born of God? All three of these answers will give us some difficulty.
First, there is no doubt that true believers sin, and 1 John addresses that directly (1 John 1:7–2:2). It's clear from 1 John 1:7 that the one walking in the light still needs cleansing from sin. It's clear that Christ Jesus is our advocate if we sin (1 John 2:2). So no, the idea that a true believer lives in sinless perfection is contradicted in 1 John.
Second, the distinction between "deliberate" and "unintentional" sin in Scripture is real. This is the main difference between the sin offering in Leviticus 4:1ff and the trespass offering in Leviticus 5:1ff. The sin offering is for sins of inadvertence, the trespass offering is for deliberate sins, like defrauding one's neighbor, or giving false testimony (Leviticus 6:1ff). So that's a real thing.
But to make 1 John 3:8ff about inadvertent sin is to ignore passages like 1 Corinthians 5:1ff. Do we really want to say the man and woman committing incest in Corinth were doing it inadvertently? Like, they didn't notice it at the time? But at least the man was repentant after the fact (2 Corinthians 7:8ff). Do we really think he was born of God in the interval between 1 Corinthians 5 and 2 Corinthians 7? We might look at Galatians 2:11ff too: was Peter not yet regenerated when he denied the Gospel by his actions towards the Gentiles?
So no, 1 John 3:8ff is not about deliberate sins as opposed to unintentional sins.
Third, making 1 John 3:8ff about the "practise" of sin gives us some difficulty with Romans 7:14–21. There we have the positive statement that a man who is regenerated practices sin, even though he abhors it. In fact, "practise" is used five times in that passage: four times in the context of practicing sin, once in the context of practicing righteousness.
Romans 7:14ff gives us some context to help us understand 1 John 3:8ff. It's not that the true believer doesn't sin, nor that the true believer doesn't intentionally sin, nor even that the true believer can't go on in a sinful way for a very long time, practicing sin. The big question is, does he or she abhor it? Does that person look at his or her actions, see they don't measure up, and then just shrug and go on? Or does that person struggle with sin?
(As an aside, I do not take the more Reformed position that Romans 7:7ff describes what we might call the "normal Christian life." I think Darby is fundamentally correct in his understanding that Romans 7:5–6 describes a transition from "when we were in the flesh" (v. 5) to "now we are clear from the law" (v. 6). And I agree that Romans 7:7ff is the fuller description of "when we were in the flesh," while Romans 8:1ff is the fuller description of "now we are clear from the law." So yes, I agree with Darby that Romans 7:7ff is not normal Christianity. But I would be quick to add the Romans 8:13 warns us that it's always possible to end up back in that same place, even once we have experienced the deliverance of Romans 8.)
So while we might look at 1 John 3 and see in it a simple test, there are other passages to consider. True believers can certainly "practise" sin, Romans 7 is explicit. True believers can deliberately sin, Galatians 2 makes that clear. True believers can fall into sin in their daily walk, 1 John 1 contemplates this exact scenario.
While I would caution against glibly accepting that anyone who is living in [apparently] unrepentant sin is a believer, I would also say that 1 John 3:8ff is no call to our being gatekeepers of salvation.
Bear in mind, too, there might be any number of people looking at you and thinking the same thing.
This probably ties in more with the notion of inadvertent sin, but it's worth a mention here. Let me start with an example: I am convinced that it's sin to eat blood. It is forbidden several places in Scripture (Genesis 9:1ff, Leviticus 17:10ff, Acts 15:19–20). It is forbidden to Noah and his sons (which certainly includes us), to Israel under the Law, and to Gentile believers in the Church. There are several Christian groups who don't seem to have a problem with eating blood, as evidenced by the fact that blood pudding, black pudding, and blood sausage survive still in Christendom. So all those Presbyterians and Anglicans who eat black pudding – as far as I can tell – are living in inadvertent sin. In fact, they're practicing that sin. But you don't see me telling them they're unregenerate. And I don't believe that means they're unregenerate, even though I am fully convinced they are continuing in sin.
My point, of course, is that every one who sets him or herself up as a gatekeeper of salvation brings condemnation on him- or herself. Do you see something in someone else's life that makes you certain they're not born again? Don't be blind to the fact that there's probably something in your life that makes someone else certain you're not regenerate either.
And no, I am not saying we should all just say, "I'm OK, you're OK." That's not at all my point.
My point is that when our first reaction to seeing sin in someone's life is to question their justification, regeneration, or salvation, then we are acting in practical Pharisaism. We are deceiving ourselves about our own sinfulness. We are forgetting how lost we really are. We are presuming on God's grace, while (at least mentally) denying that He can have that same grace on someone else.
