First John 5:16 notes, "If anyone sees his brother committing a sin not leading to death, he shall ask, and God will give him life—to those who commit sins that do not lead to death. There is sin that leads to death; I do not say that one should pray for that." What is this sin that leads to death?
What is the sin that leads to death, or the sin unto death, that John talks about?
Many interpretations exist regarding this "sin that leads to death." Unfortunately, the text is not clear what this "sin" is. It does appear clear John wrote to believers and was speaking of physical death. For example, Ananias and Sapphira experienced physical death for their sin (Acts 5). In 1 Corinthians 11:30, Paul wrote concerning wrongful practice of the Lord's Supper, "That is why many of you are weak and ill, and some have died."
In addition, the text does not refer to a specific "sin" (singular) leading to death but to "sins." In other words, there is no one sin that leads to physical death for the believer. Instead, there are certain sins that can lead to the death of a believer. This may be what Paul had in mind when he wrote, "If anyone's work is burned up, he will suffer loss, though he himself will be saved, but only as through fire" (1 Corinthians 3:15).
Further, Paul also appeared to have this idea in mind in 1 Corinthians 5:4-5 where he commanded, "When you are assembled in the name of the Lord Jesus and my spirit is present, with the power of our Lord Jesus, you are to deliver this man to Satan for the destruction of the flesh, so that his spirit may be saved in the day of the Lord." A church member bragged about his sexual relationship with his stepmother. Paul told the church to remove the man from the fellowship of the church as an act of discipline. In this case, the man appears to have later repented and been restored to fellowship (2 Corinthians 2:6-11).
The most likely explanation is that "sin that leads to death" refers not to one kind of sin, but to the kinds of sins that lead to physical death of the unrepentant believer. But how can we know if a person is committing sin leading to death? In many cases, this will not be known. However, a believer who willfully sins without repentance is to be disciplined and removed from fellowship. Unless the person repents, the person's sins will lead to God's further judgment and possibly death.
An interesting note regarding this explanation is that a true believer does not lose his or her salvation due to sin. However, God may cut a sinning believer's life short. This may be due to an act of discipline or in order to keep the person from sinning further and dishonoring God and His church.
The answer to this issue is to live a holy life before God, seek the good of other believers, and to pray for one another during times of weakness so that God would bring sinning believers to repentance and restored fellowship rather than judgment and death.
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