All sin leads to spiritual death if not confessed and forgiven by the Lord.
If anyone sees his brother sinning a sin which does not lead to death, he will ask, and He will give him life for those who commit sin not leading to death. There is sin leading to death. I do not say that he should pray about that. All unrighteousness is sin, and there is sin not leading to death. 1 John 5:16-17
There is only one sin that we are not to pray about, that leads to eternal death, and can not be forgiven.
Blasphemy of the Holy Spirit.
JLB
Well, that is technically not true that there is only one sin that leads to eternal death, my friend. We were just talking about the sin of apostasy (Which is not forgivable), too. Also, the sin of suicide or self murder with the person remaining dead is also another unforgivable sin. For there is no forgiveness after the grave to repent of suicide. A person has to seek forgiveness with the Lord while they are still alive. For it is appointed unto men once to die, but after this: the Judgment (Hebrews 9:27). There is also the sin of worshiping the beast. This is the kind of sin that is so bad that a person's name would not be written in the book of life since the foundation of the world (if they were to commit this kind of sin) (See: Revelation 13:8, and Revelation 17:8).
What is the "
sin unto death"? Well, in order to discover the "
sin unto death," we should identify what the "
sin NOT unto death" is (So as to make a contrast with the "
sin unto death"). In order to help determine what the "
sin not unto death" is in 1 John 5, I believe it is helpful to look into the motivations behind why the faithful believers are praying for the other believer who is committing a "
sin not unto death." 1 John 5 says that they are praying for this believer to have "life" (i.e. victory). But what if this believer (who is committing this sin) is prodigal and they currently do not want victory (or life) over sin in their lives? In other words, the text makes the most sense that the "
sin not unto death" is referring to 1 John 1:9 in that the believer (who is committing the "
sin not unto death") is struggling with some kind of sin and they are confessing this sin so as to be cleansed of it. They are confessing this sin with the intention of "
sinning not" (1 John 2:1) and with the intention of "
walking in the light" (1 John 1:7) (Note: Walking in the light = loving your brother - See: 1 John 2:9-11). Note: A part of loving your neighbor is keeping the Moral Law (like: Do not murder, do not steal, do not commit adultery, etc.), see: Romans 13:8-10. Anyways, the faithful brethren are praying for this believer who is committing this “sin
not unto death” in the fact that they know that he/she is confessing and seeking to overcome this sin (i.e. Their prayers is so that they may gain victory or life over this sin).
Also, the apostle John does not mention anything about the blasphemy of the Spirit in his epistle beforehand. Going by the context of the epistle of John itself, the "
sin unto death" is any grievous sin (or mortal sin) that is not confessed to the Lord.
As for not praying for for those who commit a "
sin unto death:" John is correcting a misunderstanding. He saying to the brethren that "
the sin unto death" is not what he was referring before in a previous conversation with them in regards to praying for the brethren in regards to sin. I don't believe John is advising the brethren to not pray for another believer who is committing the "
sin unto death." John is merely correcting the brethren on a misunderstanding on what he was talking about before.
"...I am talking about people whose sin does not lead to eternal death. There is sin that leads to death. I do not mean that a person should pray about that sin." (1 John 5:16) (ICB).
In other words, John was saying, "I do not mean that my previous talk to you on this beforehand that you should pray about that kind of sin; That is not what I was referring to before."
The "
sin unto death" is any grievous sin (or mortal sin) that is not confessed or forsaken. It sounds like John had a previous talk or written communication with them on this topic, and the brethren needed clarification on what he meant by praying for another brother who struggled with sin.
Anyways, in context of John's 1st epistle, we learn that the whole contrast is between those believers who say they know the Lord, and do not keep His commandments (1 John 2:4), vs. the righteous who do know the Lord because they keep His commandments (1 John 2:3). For he that commits sin is of the devil (1 John 3:8), and he that does righteousness is righteous (1 John 3:7). For there are those who say that they don't sin even when they do sin (1 John 1:8), vs. those who stumble on occasion and confess their sins so as to be forgiven of sin (1 John 1:9). This is the context or view of what John was talking about in 1 John 5 and it was not the blasphemy of (speaking bad words against) the Holy Spirit.