Question: In 1 John 5:16, what is meant by “sin not leading to death,” and is the person who witnesses the sin being committed able to confess and repent for the sinner?
This is probably one of the most difficult verses in the New Testament, leading to many different explanations. And the question, what is meant by “sin not leading to death,” gets at the heart of the problem, because all sin leads to death (Rom. 6:23).
The verse tells us that the person committing the sin (whatever it is) is a “brother” (i.e., a believer); and the phrasing in the Greek makes it clear that this follower of Jesus is committing this sin intentionally (Gk. aJmarta¿nonta aJmarti÷an: “sinning to sin”). And whatever this sinful behavior is that the follower of Jesus is about to act upon “does not lead to death.”
We know from Scripture in general that all sin that is not atoned for by the blood of Jesus ultimately leads to judgment and death—complete, eternal separation from God physically and spiritually:
Rom. 6:23 For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
Matt. 25:41 “Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. 46 “Then they will go away to eternal punishment, but the righteous to eternal life.”
Therefore, the word “death” in 1 John 5:16 must refer simply to physical death, not eternal condemnation. In that case, the verse tells us that there is some sin that leads to physical death and other sin that does not. The verse goes on to say that when one believer sees another believer tempted to act in a sinful way, he should ask God to give his tempted friend “life.” This word for “life” (Gk. zwh/) can also mean “the way of life.” In other words, we should pray that God would steer our tempted brother or sister away from sin and toward the path of obedient life in Christ.
But that still leaves the question: What kind of sin does lead to physical death, and are we supposed to let someone about to commit that kind of sin go un-prayed for?
There are some examples of sin leading to physical death recorded in Scripture. Ananias and Sapphira lied to God, and when their sin was exposed they collapsed and died on the spot (Acts 5:1-10). Some believers in Corinth who selfishly abused the Lord’s Supper, stuffing themselves with food, became sick. Some even died, as a judgment by God (1 Cor. 11:27-34). Likewise, the apostle Paul warns believers to avoid sexual immorality, using the experience of the Hebrews in the Wilderness as an example:
1Cor. 10:8 We should not commit sexual immorality, as some of them did—and in one day twenty-three thousand of them died.
Finally, the word translated “pray” at the end of 1Jn. 5:16 specifically means “interrogate,” “question” or “ask.” So when God does exercises capital punishment upon the believer, this verse tells us we should not question God about His decision to do so.