I think you give a strained exegesis here. Making 16b completely distinct from 16a is a strange reading of the text. As I see it, this is the logic of the text: "If you see your brother sinning and the sin is not deadly, then pray and he will be given life. If the sin is deadly then do not pray for him." The idea that 16b refers to a completely different object than 16a makes the text strangely disjointed, as if their juxtaposition is entirely coincidental. That is, you are claiming on the basis of an argument from silence that 16b refers not to a "brother" but to an outsider, an unbeliever, the unrepentant, etc. I think it is an undue warping of the text, particularly when the entire chapter is centered on believers (apart from 10b and 12b).
zippy, I think the interpretation I offered is bolstered when examining the broader context of John’s first epistle and the themes he develops throughout. In the second chapter, John warns of the antichrists that have come into the community of believers only to fall away. He tells his audience that this happened because they were never “of us”, that is, of the body of true believers.
18 Children, it is the last hour, and as you have heard that antichrist is coming, so now many antichrists have come. Therefore we know that it is the last hour. 19 They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us. - 1 John 2:18-19 (ESV)
He goes on to define antichrist as one who rejects both Jesus as Christ and his Father.
22 Who is the liar but he who denies that Jesus is the Christ? This is the antichrist, he who denies the Father and the Son. 23 No one who denies the Son has the Father. Whoever confesses the Son has the Father also. - John 2:22-23 (ESV)
He says that those who hold to what they “heard from the beginning” (the gospel, see 1 John 1:1-5) will receive eternal life. This is contrary to the antichrists who deny Christ and thereby his gospel. The latter do not have eternal life.
24 Let what you heard from the beginning abide in you. If what you heard from the beginning abides in you, then you too will abide in the Son and in the Father. 25 And this is the promise that he made to us—eternal life. - 1 John 2:24-25 (ESV)
In the beginning of chapter 4, John states that anyone who denies Jesus as God has the spirit of antichrist in him. These people resist the doctrine of the church and have a “spirit of error” (1 John 4:6).
2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God, 3 and every spirit that does not confess Jesus is not from God. This is the spirit of the antichrist, which you heard was coming and now is in the world already. - 1 John 4:2-3 (ESV)
John makes clear that all who believe in the Son have life. Conversely those who do not believe in the Son do not have life. These will be consumed by eternal death and punishment.
10 Whoever believes in the Son of God has the testimony in himself. Whoever does not believe God has made him a liar, because he has not believed in the testimony that God has borne concerning his Son. 11 And this is the testimony, that God gave us eternal life, and this life is in his Son. 12 Whoever has the Son has life; whoever does not have the Son of God does not have life. - 1 John 5:10-12 (ESV)
Finally, in the conclusion to his epistle, John speaks of “sin not leading to death” and “sin that leads to death” (1 John 5:16-17). With the preceding passages having established the identify of antichrist and the sin of apostasy, and with this contrasted by those who hold fast to the faith, though they still sin (1 John 1:8), I think we can reason that the “sin that leads to death” is in reference to those who reject Christ and his gospel as evidenced by their walking away from the faith. John is clear that God is faithful toward those who confess their sins (1 John 1:9). But of those who impenitently deny Christ as savior? These are those who I believe commit sin that leads to death.
I found several commentaries which touch on this point and may be of interest to you.
Simon Kistemaker
“If anyone sees his brother commit a sin that does not lead to death.” When John writes “brother” in his epistle, he means a fellow believer. Whenever a member of the Christian community notices that a brother is falling into sin, he should pray to God on his behalf (compare James 5:20).
John distinguishes between “a sin that does not lead to death” and “a sin that leads to death.” In this passage he mentions the first kind three times and the second only once. He clearly implies that praying for the sinner who commits “a sin that does not lead to death” is the intent of his writing.
What is the meaning of the word death? In addition to 5:16, where it occurs three times, the word appears twice in 3:14: “We know that we have passed from death to life, because we love our brothers. Anyone who does not love remains in death.” John is not thinking of physical death. Rather, he is referring to spiritual death. He contrasts death with eternal life (3:15) to set apart the believer, who possesses this life, from the person who denies that Jesus is the Son of God (2:22–23) and who hates the believer (3:13).
Who, then, commits the sin that leads to death? The person who rejects Jesus as the Christ and who does not love the believer commits this sin. He does not share in the fellowship of the Father and the Son (1:3), and is excluded from eternal life (4:12). He left the Christian community because he did not really belong to it (2:19). He had been a pretender.
[...]
“All wrongdoing is sin, and there is sin that does not lead to death.” John calls attention to the seriousness of sin. “Sin is lawlessness” (3:4) and is always an affront to God. In fact, in the sight of God, sin is a transgression of his law and the person who “stumbles at just one point is guilty of breaking” the whole law (James 2:10).
But not every sin leads to death. When a believer transgresses God’s law, he does not deny the sonship of Christ and hate the church. Moreover, God stands ready to forgive his sin. John teaches that “if we confess our sins, [God] is faithful and just and will forgive us our sins and purify us from all unrighteousness” (1:9). God forgives sin when the sinner confesses and fellow Christians pray for him, for “God will give him life.”
Kistemaker, S. J., & Hendriksen, W. (1953–2001). Exposition of James and the Epistles of John (Vol. 14, pp. 362-364). Grand Rapids: Baker Book House.
John Calvin
There is a sin unto death I have already said that the sin to which there is no hope of pardon left, is thus called. But it may be asked, what this is; for it must be very atrocious, when God thus so severely punishes it. It may be gathered from the context, that it is not, as they say, a partial fall, or a transgression of a single commandment, but apostasy, by which men wholly alienate themselves from God. For the Apostle afterwards adds, that the children of God do not sin, that is, that they do not forsake God, and wholly surrender themselves to Satan, to be his slaves. Such a defection, it is no wonder that it is mortal; for God never thus deprives his own people of the grace of the Spirit; but they ever retain some spark of true religion. They must then be reprobate and given up to destruction, who thus fall away so as to have no fear of God.
Matthew Henry
Then there are sins which, by divine constitution, are unto death; and that either death corporal or spiritual and evangelical. First, Such as are, or may be, to death corporal. Such may the sins be either of gross hypocrites, as Ananias and Sapphira, or, for aught we know, of sincere Christian brethren, as when the apostle says of the offending members of the church of Corinth, For this cause many are weak and sickly among you, and many sleep, 1 Cor. xi. 30. There may be sin unto corporal death among those who may not be condemned with the world. Such sin, I said, is, or may be, to corporal death. The divine penal constitution in the gospel does not positively and peremptorily threaten death to the more visible sins of the members of Christ, but only some gospel-chastisement; for whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth, Heb. xii. 6. There is room left for divine wisdom or goodness, or even gospel severity, to determine how far the chastisement or the scourge shall proceed. And we cannot say but that sometimes it may (in terrorem—for warning to others) proceed even to death. Then, Secondly, There are sins which, by divine constitution, are unto death spiritual and evangelical, that is, are inconsistent with spiritual and evangelical life, with spiritual life in the soul and with an evangelical right to life above. Such are total impenitence and unbelief for the present. Final impenitence and unbelief are infallibly to death eternal, as also a blaspheming of the Spirit of God in the testimony that he has given to Christ and his gospel, and a total apostasy from the light and convictive evidence of the truth of the Christian religion. These are sins involving the guilt of everlasting death.
Granted, 1 John is a polemical letter, and theology of "the elect" is probably at work in the background, but at the same time it is undeniable that the author distinguishes deadly from non-deadly sin in vv. 16-17.
I do not deny that John distinguishes “sins that do not lead to death” from “sin that leads to death”. I deny that “sin that leads to death” refers to sin that causes a true believer to fall outside of saving grace. I think it refers specifically to apostasy, which John identifies with antichrist in the letter.
In general I find it unproductive to argue with those who hold to OSAS because no matter what I say--and no matter what scripture is produced (e.g. Hebrews 6:4-6)--the answer is always, "Oh, those who fell away were not part of the Elect."
I am not among the OSAS camp because I believe it fails to teach the importance of genuine repentance in the process of sanctification. It gives people the impression that if they just say a sinner’s prayer at some point that they can then impenitently deny the gospel for the rest of their lives while their once-made statement counts to secure a salvation they had never received through faith. John identifies those people as antichrist who never possessed true faith.
It seems that your principle that the Elect never stumble and require repentance is both unfalsifiable and unScriptural. That is, scripture nowhere supports this doctrine of yours, even if for the sake of argument we posit that it nowhere denies it.
I do not believe I have said in this thread that the elect “never stumble and require repentance”. John’s point in 1 John 5:16 is to pray on behalf of those who do stumble! I’m taking issue with the notion that a true believer can fall from saving grace if they commit certain (mortal) sins.
Let me put this question to you: If scripture did teach mortal sin, what would it say? What would that teaching look like? (My guess is that your answer would be, "There is sin which, unrepented of, leads to death. The non-Elect will commit such sins and fall away. The Elect may commit such sins, but if they do, they will repent and be restored.")
zippy, I hold that Christ’s death satisfied the wrath of God against
all sins of the elect. Thus, it would be impossible for one of the elect to commit a sin that would put him outside of God’s grace. I truly think that the issue here is that we have different views of the intent and extent of Christ’s atonement.