About sin-unto-death
1 John 5:16-17
16 If someone sees their brother or sister sinning a sin 'not-unto-death', they should ask and He [God] will give life to those sinning 'not-unto-death'.
There is a sin 'unto-death'; I don't mean that kind of sin, that they should pray [for a person committing it]. 17 Every wrong act is a sin, and there is a sin 'not-unto-death'.
The other day I wrote about the terrifying confidence of vv14-15 in this chapter, and I thought I'd just go on straight on and write about these next two verses, which I have also wrestled with. The connection between 16 and 14-15 hinges on the command to pray, and so the particular confidence in prayer that John has in view in 14-15 applies to v16 which is a command to pray for something in particular. And so 16 lays out (i) a situation (ii) a command, (iii) the confidently-expected outcome. But then the second half of this verse gets... trickier.
The easy part.
The situation: If someone sees their brother or sister sinning a sin 'not-unto-death'
I think this is the easy part of understanding what John is saying, because the situation is visible and tangible. You, a believer, observe another believer committing some sin. It's a sin that 'doesn't lead to death'. John clearly has two functional categories of sin: (i) unto death, and (ii) not unto death. Against the backdrop of the whole letter, and in light of what I think is going on in chapter three, this is how I understand them:
Sin unto death: is sin that cannot be forgiven, because it's the fundamental sin of rebellion against God and rejection of Jesus. Since Jesus is the only means of forgiveness, rejecting Jesus as Messiah, and his atoning death, means that there is no other means of forgiveness available. By definition, refusing and rejecting Jesus means one isn't a believer in Jesus.
Sin not unto death: is sin that can be forgiven and is (going-to-be) forgiven. It's the sin of a believer who (characteristically) confesses their sin (1 Jn 1.8)
The command: they should ask
And so John's instruction is straightforward. You should pray for the forgiveness of fellow believers when you see them sin. He actually frames this with a future tense (they will pray), but this is reasonably understood as a command. John places a responsibility for the spiritual health of the community on mutual intercession.
The promise: He will give life to those sinning 'not-unto-death'
And the outcome is not in doubt, which is that God will forgive that (sinning) person. That confidence is grounded in the understanding that God through Christ forgives the sins of believers. And that forgiveness is operational, it 'works', by the believer trusting in Jesus' death, and through the normal means of confession and repentance. It's noteworthy, though, that John doesn't tell believers to pray for other believers to repent!
The trickier part
There is a sin 'unto-death'; I don't mean that they should pray for a person committing that kind of sin
You'll notice I've switched up the translation a little. John's sentence at this point is highlighting what he's not saying. That is, John wants his readers to know that he's not telling them that they should pray for a person committing 'sin unto death'. Why such a confusing statement? Here are all my best thoughts and readings:
John neither prohibits nor commands. If John wanted to prohibit prayer for them, based on his forthright no-holding-back statements elsewhere, I don't see why he wouldn't just say so. Instead, he refrains from making a definitive claim either way. Which means there is freedom here, to pray or not to pray.
In a broader Scriptural and theological view of the matter, even rejecting Jesus is not a sin that can't be forgiven, in that turning back to God from a defiant position of hostility is possible, and to be hoped for.
The limits of our knowledge mean we don't know if denying Jesus is a 'Peter moment' or a 'Judas moment' in any individual's life.
The confidence that John just extended about God forgiving a sinning brother or sister is not a confidence that shapes our prayers for those who reject Jesus.
The shape of prayers for those who have left, or been put out of, the church, is virtually equivalent to prayers for those who have never known Jesus in the first place.
Why might there be caution about praying for such a person? I found a particularly insightful comment in Yarbrough's commentary, that as when God told Jeremiah to stop praying for his fellow Israelites, so too there may come a time when for one's own sake you should stop praying. There may be a danger in advocating for someone before God, that one identifies so much with the transgressor, and becomes disillusioned at God's response, that one chooses to side with the transgressor against God.
In light of the final words of v17, though, it is difficult to assess whether any particular moral offense is 'sin unto death'; but if the greatest good for a human being is God himself, to know and live in him; then the worst evil that can befall them is to turn away from the Good, from God, and to oppose him forever. That moves me to sadness for the many I have known who have walked away from their faith, and to prayer for the repentance that leads to life.