16 If anyone sees his brother commit a sin that does not lead to death, he should pray and God will give him life. I refer to those whose sin does not lead to death. There is a sin that leads to death. I am not saying that he should pray about that. 17 All wrongdoing is sin, and there is sin that does not lead to death.

Various interpretations have been put forward:-

1. That the difference is between intentional and unintentional sins.  These are sometime distinguished in the OT (Lev. 4:1–3; Num. 15:22–31; Ps. 19:12–13), but there is no evidence that this is John’s intention here.

2. That the difference is between more heinous, and less heinous, sins.  Roman Catholic teaching, for example, distinguishes between ‘mortal’ and ‘venial’ sins.  The doctrine of Purgatory is thus ‘proven’ for it is here that the individual will be purged from ‘venial’ sin.

Jackman (BST) writes:

‘The traditional Roman Catholic view is that there are two categories of sin: “venial” (pardonable), and “mortal” (sin that leads to death).  The seven deadly sins are literally so, though the sacrament of penance, prescribed by the church through the priest, is designed to be a work of penitence by which satisfaction for sin can be made.  The text, however, offers no support for such a division of sins, much less for a list of mortal sins.  In the Bible’s view every sin is mortal, since every sin pays the wage of eternal death (Rom 6:23).  Further, the New Testament offers no support for the belief that any human work can justify the guilty sinner.  Indeed, this very letter of John reminds us that only the sacrifice of the Son of God can atone for sin by turning away God’s wrath (e.g. 1 Jn 2:2; 4:10).’

3. That the sin that leads to death is a sin that, as in the case of Ananias and Sapphira (Act 5:1–11; cf. 1 Cor 11:29–30), has led to actual physical death.  In this case, the apostle is prohibiting prayers for the dead.  This is the opinion of Bruce.  Blomberg, however, thinks that this interpretation is ‘unlikely’, since John habitually refers to both life and death in their spiritual sense.

4. That the sin that leads to death is the blasphemy against the Holy Spirit (cf. Mk 3:28-30).  Stott favours this interpretation, and Ross regards it as ‘possible’.

5. That the sin that leads to death is the persistent rejection of the truth.  Ross quotes David Smith:

‘There is a fearful possibility of a man putting himself beyond the hope of restoration: but we can never tell when he has crossed the boundary.  If we were sure it was a case of “sin unto death,” then we should forbear praying; but since we can never be sure, we should always keep on praying.’ These are wise words, but rather distant from what seems to be John’s meaning here.  John cannot really be talking about persistent sinning when what he actually refers to is ‘a [specific] sin’.  Cotton, discussing the view that the ‘sin unto death’ is ‘final impenitence’ observes that this ‘cannot be discerned until after death, and so his direction [not to pray for such persons] would have been but frivolous.’

6. That the sin that does not lead to death is the sin of believers, and the sin that leads to death is the sin of unbelievers.   Perhaps especially in mind are those who actively oppose the gospel (so Cotton), including the secessionists (so Johnson and Kruse).  True believers to not ‘continue in sin’, but unbelievers do: they sin against God’s law and against their of conscience; they do so deliberately and repeatedly.  To ask God to forgive any particular sin, when that person has no intention of quitting a life of sin, is pointless.

Kruse says:

‘The ‘sin that does not lead to death’ is the sin believers commit and for which forgiveness has been secured by the atoning sacrifice of Christ (cf. 1 Jn 1:9; 2:1–2).’  They who have denied that Christ has come in the flesh and that his death is necessary for salvation.  They have not the Spirit of Christ, but rather the spirit of antichrist.  They are, to use other scriptural language, ‘perishing’, ‘death in their trespasses and sins’, ‘without hope and without God in the world.’

Johnson writes:

‘the real distinction in vv. 16–17 is the same distinction we have observed all along in 1 John (and which continues in 2–3 John), i.e., between the Elder’s faithful followers, who “believe in the name of [God’s] Son, Jesus Christ, and … love one another” (1 Jn 3:23) and the antichrist, false prophet, secessionist, worldly, lying and deceiving children of the devil, who deny Jesus and hate their brothers (1 Jn 2:18–19, 22–23; 3:10, 15; 4:1–3, 5; 2 John 7).’  ‘They are continuing in (and therefore condoning) sin, they are hating and separating from their fellow Christians (thus not living out the command of love), they love the world and they even deny that Jesus has come “in the flesh” (probably a denial that Christ had a real human body). These are not casual errors or lapses into this or that sin, but a knowing and deliberate turning away from the truth they experienced in the Christian community’ (HSB).

Johnson adds that the apostle only refers to those who commit a sin that does not lead to death as ‘brothers’, not those who commit a sin that does lead to death.   They are outside the community of faith, even though they may once have seemed to be bone fide believers.  John is not forbidding praying for such people; he is, rather, saying that is not his point at the present time.  He is speaking of praying for those within the fellowship who fall into sin, not those outside the fellowship who are (at present) living in settled rebellion against God.  In a word, the ‘sin that does not lead to death’ is the lapse of a person who has received new life in Christ.  Such a person may, with the help of the prayers of fellow-believers, may readily be restored to fellowship with God.

The ‘sin that leads to death’ is the sin which is symptomatic of an unregenerate nature.  To pray for the forgiveness of such a sin would be beside John’s point here, because what that person needs is not forgiveness of this or that lapse, but a spiritual resurrection.

Cotton notes that though Paul bids us pray for all men (2 Tim 2:1), yet he seems to agree with John’s exception here.  For Paul himself

‘is so far from praying for them that he prays against them, that they may be rewarded according to their works, 2 Tim 4:15…He wishes they were utterly cut off from church and commonwealth, Gal 5:12.’

After considering other, more plausible, interpretations of this verse (including the possibility that it refers to the ‘blasphemy against the Holy Spirit’, Mt 12:31f), Jackman sets out his own view that what John is referring to here is not ‘unpardonable’ and ‘pardonable’ sin, but ‘unpardoned’ and ‘pardoned’ sin.  This is consistent with the teaching of this letter as a whole.  The ‘sin that does not lead to death’ is sin that has been cleansed by ‘the blood of Jesus’, 1 Jn 1:7; it has been ‘forgiven’, 1 Jn 2:12.

There is a certain irony in the fact that, in a passage so concerned with certainty, there should be this teaching, of whose meaning we feel rather uncertain.