There are at least two applications for these verses: the first for people who, for one reason or another, have left the church of God, His truth, and His way of life; and a second for those who are still actively in the church. The most common misinterpretation of this verse is the claim that it proves there are some sins a person can commit and not incur the penalty of eternal death. Can this be true?
In short, no! It cannot be true. We know very well that the wages of sin is death (Romans 6:23). To this, there can be no exceptions! God does not categorize sins this way. Instead, the Bible distinguishes sins differently. Through the author of the book of Hebrews, God shows us that "willful" sin brings the second death - eternal death:
For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries. (Hebrews 10:26-27)
Please hold onto the word, "willfully." We will come back to it presently.
Of course, any sin can be forgiven if it is sincerely repented of, and if it is "confessed," not to a human priest or minister, but to our merciful God: "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:9). Conversely, any sin can also lead to eternal death if it is not confessed and repented of, and if it is allowed to continue repeatedly in a person's life. A "sin not unto death," then, is one that is confessed, repented of, and does not involve a willful violation of God's law.
On the other hand, a person has "sinned unto death" if he has willfully turned from God's way. It is gradually becoming clear that this whole matter revolves around this word "willfully" from Hebrews 10:26. The Greek word is hekousios, and it means "voluntarily" or "willingly." The English adverb stems from the adjective "willful," which means, according to The Merriam-Webster Dictionary:
» obstinately and often perversely self-willed;
» done deliberately;
An extensive and profitable Bible study could be conducted just on these four alternate renderings of the word "willful." The first three meanings generally speak for themselves, but the fourth and last one seems to show willfulness in its true shade. Those who are unruly are continuously unwilling to obey the rules, in this case, God's rules! They unceasingly refuse to accept God's government and His laws.
Sin unto death may not necessarily include all those who have apparently left the church, nor even all those who have been disfellowshipped, but only those who have willfully rejected God's way to the extent that it is no longer possible for them to be brought to repentance. However, this is certainly not suggesting that it is acceptable for a person to take God's loving mercy for granted, to think that he can leave God's church to "enjoy a little sin" for a while, then simply jump back in at a convenient, later date. Such devices or actions carry with them some obvious and very real dangers, bringing to mind another well known but somewhat fearsome biblical passage:
For it is impossible for those who were once enlightened, and have tasted the heavenly gift, and have become partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, if they fall away, to renew them again to repentance, since they crucify again for themselves the Son of God, and put Him to an open shame. (Hebrews 6:4-6)
This should be an arresting, solemn, and even terrifying warning for any who might consider leaving the church. Obviously, it is often very difficult for any fellow human being to determine who has and who has not "crossed the line." In fact, it is probably because of the extreme difficulty of discerning when this is the case that the apostle of love writes in our difficult scripture, "I do not say he shall pray for it" rather than the sterner alternative command, "He shall not pray about it."
John's open-ended statement allows for a Christian's natural desire to hope that the person has not gone too far - to hope that he will repent - and he does not prohibit intercessory prayer, even in such a case. We should rather err on the side of praying for our errant brethren than not praying. John implies that our prayer may be futile, but he does not say that it is a sin to pray even for a seemingly hopeless case, as long as we do not know for sure that it is totally hopeless.
Finally, let us bring this subject around to include those who are still in God's church. If any of us sees or hears of a fellow church member who is normally striving to obey God "sin a sin which is not unto death" - often out of ignorance or weakness - we ought to ask God to help the member recognize his error and repent of it. When we do so, God will hear and answer our prayers and may, according to His will, "give him life": "And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him" (I John 5:15). This is the kind of concern we must have for all of our spiritual brothers and sisters, and it is one way that we can "bear one another's burdens, and so fulfill the law of Christ" (Galatians 6:2).
Through our deeper study into a relatively complex scripture, God reveals two simple conclusions: Should we pray for a fellow member if we see or hear of him sinning? Yes, we should. And should we pray for friends and loved ones who have left God's truth? Again, yes, we should, for "The effective, fervent prayer of a righteous man avails much" (James 5:16).