“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.”
There is sin leading to death.
There is a sin where prayer is not effectual. This is an exception to the general rule that God answers all prayers prayed in His will. It is useless to make a request about a person committing the sin unto death because he is under God’s sentence of death.
The reference here is not to the sin that leads to spiritual death – that is, eternal separation from God. All sin ultimately leads to death (Ro 6:23), but that is not the meaning here. The idea here is that a Christian can die a premature physical death because of prolonged and intransigent carnality.
I do not say that he should pray about that
The word “pray” is a different Greek word than the word “ask” earlier in the verse. The idea of “pray” is request, inquire. John does not encourage his readers to inquire about the healing of an intransigent Christian because the carnal Christian is volitionally shut down to God. That is a matter between the carnal Christian and God. God has His way of dealing with the obstinate.
Christians living in protracted sin can reach a point of being under a sentence of physical death.
Most sins that Christians commit do not result in immediate physical death or a sentence of physical death. That is why we can pray for them.
He 13: 18 “Pray for us; for we are confident that we have a good conscience, in all things desiring to live honorably.”
Ja 5: 14 “Is anyone among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord. 15 And the prayer of faith will save the sick, and the Lord will raise him up. And if he has committed sins, he will be forgiven. 16 Confess your trespasses to one another, and pray for one another, that you may be healed. The effective, fervent prayer of a righteous man avails much.”
Prayer will not prevent the “sin unto death.” There is no sense in praying for someone who is implacably and incorrigibly obtuse. Some Christians enter into such a state of carnality that they head for divine discipline that takes on the nature of physical death (5:19-20; Pr. 10:27; 11:19; 13:14; 19:16). Prayer for the carnal Christian is not the same thing as prayer for the Christian under God’s death sentence.
1 Ti 5: 24 “Some men’s sins are clearly evident, preceding them to judgment, but those of some men follow later. 25 Likewise, the good works of some are clearly evident, and those that are otherwise cannot be hidden.”