Published: 13 July 2026

The Sin Unto Death

A Bible Study on 1 John 5:16–18

1 John 5:16–18 (KJV)

“If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it.

All unrighteousness is sin: and there is a sin not unto death.

We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not.”

Introduction

The phrase “a sin unto death” is one of the most difficult expressions in the New Testament.

What does John mean?

Is he speaking of:

physical death under divine chastening;
eternal death through apostasy;
the blasphemy against the Holy Ghost;
or some other especially serious sin?

Although several interpretations have been proposed, the immediate context of 1 John gives important clues.

This study concludes that the sin unto death is most likely settled and final rejection of Jesus Christ, revealing that the sinner does not possess the eternal life found in the Son.

At the same time, the alternative interpretation—physical death under divine chastening—remains biblically possible and should be treated fairly.

1. The Immediate Context

John’s discussion begins with assurance of salvation.

1 John 5:11–13

“And this is the record, that God hath given to us eternal life, and this life is in his Son.

He that hath the Son hath life; and he that hath not the Son of God hath not life.

These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life…”

The flow of thought is important:

Eternal life is in the Son.
The believer may know that he possesses eternal life.
This assurance gives confidence in prayer.
John then applies prayer to a sinning brother.
He distinguishes sin not unto death from sin unto death.
Verse 18 assures believers that the one born of God is preserved from the wicked one.

The subject is therefore not merely physical survival. The entire paragraph is concerned with:

eternal life;
possession of the Son;
prayer;
sin;
regeneration;
and divine preservation.

2. The Sinning Brother

John says:

“If any man see his brother sin…”

The word “brother” normally refers to a genuine believer in 1 John.

For example:

1 John 3:14

“We know that we have passed from death unto life, because we love the brethren.”

The brother in 1 John 5:16 is therefore most naturally understood as a Christian who has fallen into sin.

However, John specifically describes him as committing:

“a sin which is not unto death.”

John does not explicitly say that the brother commits the sin unto death.

The verse may therefore distinguish two cases:

a genuine brother who sins and may be restored;
a deathward sinner who belongs to a different category.

This distinction is important.

3. What Does “Life” Mean?

John has just written:

“God hath given to us eternal life.”

“He that hath the Son hath life.”

“Ye may know that ye have eternal life.”

Then he says:

“He shall give him life…”

The natural assumption is that “life” in verse 16 remains connected with the eternal life already discussed.

This creates difficulty for the physical-death interpretation, because that interpretation requires “life” to change suddenly from eternal life to bodily life.

Under the preferred interpretation, God “gives life” to the sinning brother by restoring him within the life he already possesses in Christ.

This may include:

conviction;
confession;
restored fellowship;
renewed obedience;
spiritual vitality;
and preservation from the deathward consequences of sin.

John is not teaching that the brother must be regenerated a second time.

He is describing restorative life flowing from the eternal life already found in the Son.

4. What Does “Death” Mean?

Elsewhere in 1 John, death is spiritual.

1 John 3:14

“We know that we have passed from death unto life…”

This is not a movement from physical death to physical life. It describes salvation.

The same contrast appears in:

1 John 5:12

“He that hath the Son hath life; and he that hath not the Son of God hath not life.”

The person without the Son remains in death because eternal life exists only in Christ.

Therefore, the phrase “sin unto death” most naturally refers to sin whose final direction and result are spiritual and eternal death.

5. The False Teachers in 1 John

The historical setting of the Epistle is essential.

False teachers had departed from the Christian community.

1 John 2:19

“They went out from us, but they were not of us…”

John explains that their departure revealed their true spiritual condition.

They had been outwardly associated with the church, but they were never truly of the regenerate fellowship.

Their error was centred on the identity of Christ.

1 John 2:22

“Who is a liar but he that denieth that Jesus is the Christ?”

1 John 2:23

“Whosoever denieth the Son, the same hath not the Father…”

1 John 4:3

“Every spirit that confesseth not that Jesus Christ is come in the flesh is not of God…”

These secessionists provide the most natural background for the sin unto death.

Their sin was not simply one moral failure.

It was settled rejection of Christ and the apostolic testimony concerning Him.

Because life is in the Son, rejection of the Son is necessarily deathward.

6. The Importance of Verse 18

Verse 18 is the key to understanding verses 16–17.

1 John 5:18

“We know that whosoever is born of God sinneth not…”

This cannot mean that believers become sinlessly perfect.

John has already said:

1 John 1:8

“If we say that we have no sin, we deceive ourselves…”

1 John 2:1

“And if any man sin, we have an advocate with the Father…”

The believer can sin and may fall seriously.

What John teaches is that the person born of God does not end his spiritual course in settled Christ-denying apostasy.

The verse continues:

“that wicked one toucheth him not.”

This does not mean that Satan never tempts or attacks a believer.

It means that the wicked one cannot finally seize or possess the one who is truly born of God.

The believer’s security rests upon Christ’s keeping power.

7. Can a Genuine Believer Commit the Sin Unto Death?

If the death is eternal, the answer is no.

A genuine believer may:

fall into serious sin;
backslide;
deny Christ temporarily under fear;
require discipline;
lose joy and usefulness;
and even suffer severe temporal consequences.

But a genuine believer will not finally repudiate Christ and pass from eternal life into eternal death.

John explains permanent apostasy this way:

1 John 2:19

“They were not of us…”

Their departure did not destroy regeneration.

It revealed that regeneration had never taken place.

8. What About Peter’s Denial?

Peter denied Christ three times.

Yet his denial was not the sin unto death.

Before Peter’s fall, Jesus said:

Luke 22:31–32

“Simon, Simon, behold, Satan hath desired to have you, that he may sift you as wheat:

But I have prayed for thee, that thy faith fail not…”

Peter fell grievously, but his faith did not finally fail.

He repented and returned.

This shows that the sin unto death is not simply:

one denial;
one terrible statement;
one season of fear;
or one serious moral fall.

The decisive issue is final and settled rejection of Christ.

9. Is This the Blasphemy Against the Holy Ghost?

The sin unto death is related to the blasphemy against the Holy Ghost, but the two should not be identified too quickly.

In Matthew 12, the Pharisees knowingly attributed the Spirit’s work through Christ to Satan.

Matthew 12:31

“The blasphemy against the Holy Ghost shall not be forgiven unto men.”

Both passages involve hardened rejection of divine testimony concerning Christ.

However, 1 John does not mention:

miracles;
Beelzebub;
the Pharisees;
or speaking directly against the Holy Ghost.

It is therefore better to say that both sins belong to the same broad category of hardened rejection, without insisting that they are identical in every detail.

10. Why Does John Say, “I Do Not Say That He Shall Pray for It”?

John does not say:

“Thou shalt not pray.”

He says:

“I do not say that he shall pray for it.”

This most likely means that John does not extend the same promise of assured restoration to the deathward case.

Believers are encouraged to pray confidently for a sinning brother.

But no promise is given that settled apostasy will be reversed.

This does not necessarily mean Christians must never pray for an unbeliever or apparent apostate.

Scripture teaches believers to pray for:

enemies;
persecutors;
and the salvation of the lost.

The difference is between:

prayer offered with a specific promise of restoration;
and prayer offered without such guaranteed assurance.

11. The Physical-Death Interpretation

A widely held alternative view understands death as premature physical death under divine chastening.

This interpretation argues:

the sinner is called a brother;
therefore, he is a genuine believer;
a genuine believer cannot suffer eternal condemnation;
therefore, the death must be physical;
Scripture teaches that believers may die under severe discipline.

The strongest supporting passage is:

1 Corinthians 11:30–32

“For this cause many are weak and sickly among you, and many sleep.

For if we would judge ourselves, we should not be judged.

But when we are judged, we are chastened of the Lord, that we should not be condemned with the world.”

This passage clearly teaches that believers may die physically under divine chastening without losing salvation.

Other possible examples include:

Ananias and Sapphira in Acts 5;
the immoral man in 1 Corinthians 5;
and Moses being barred from entering Canaan.

The doctrine of terminal divine chastening is therefore biblical.

The question is whether it is John’s meaning in 1 John 5:16.

12. Why the Physical-Death View Is Less Likely

Although the physical-death interpretation is possible, it faces several difficulties.

1. It requires a sudden change in meaning

“Life” means eternal life in verses 11–13 but bodily life in verse 16.

2. John does not mention bodily illness

Unlike 1 Corinthians 11, John says nothing about:

weakness;
sickness;
sleep;
bodily judgment;
or chastening.

3. It does not explain the false-teacher setting as naturally

The major conflict in 1 John concerns denial of the Son, not physical sickness among believers.

4. Verse 18 fits apostasy more directly

The believer is kept from the wicked one, which naturally suggests spiritual preservation from final satanic dominion.

For these reasons, physical death remains a respectable secondary interpretation, but not the strongest contextual reading.

13. Matthew Henry’s Understanding

Matthew Henry acknowledged that sin may result in different kinds of judgment, including temporal and bodily consequences.

However, when explaining verse 18, he wrote that the believer is secured against:

“that sin which is unavoidably unto death, or which infallibly binds the sinner over unto the wages of eternal death.”

Henry therefore understood the distinctive sin unto death as leading to eternal death.

He connected verse 18 with the preservation of the regenerate from that fatal sin.

His interpretation supports the conclusion that:

the sin unto death is spiritually fatal;
the person born of God is preserved from committing it;
and verse 18 explains the meaning of verses 16–17.

14. Final Conclusion

The strongest interpretation is:

The sin unto death is settled, informed, wilful, and final repudiation of Jesus Christ and the apostolic testimony concerning Him. It is unto death because the person who rejects the Son rejects the only source of eternal life. Such apostasy does not cause a genuinely saved person to lose salvation; it reveals that the apostate was never truly born of God.

The genuine brother may sin seriously.

But he remains the object of prayer and restoration because God’s preserving life is at work within him.

The apostate rejects the Son and therefore remains without life.

Verse 18 then provides assurance:

the one born of God is kept, and the wicked one cannot finally seize him.

15. Doctrinal Summary

Eternal life is found only in Jesus Christ.
Every genuine believer possesses eternal life.
Believers still sin after salvation.
All unrighteousness is serious.
A fallen believer should be prayed for and restored.
The sin unto death is most likely final Christ-denying apostasy.
It reveals the absence of regeneration rather than the loss of salvation.
Verse 18 assures believers of divine preservation.
John does not teach sinless perfection.
Physical death under divine chastening is a separate biblical doctrine.
A believer may die under chastening without losing salvation.
Christians should not casually declare a living person beyond repentance.
The church’s normal response to a fallen brother should be prayer, truth, discipline, and restoration.

16. Pastoral Applications

Pray before condemning

John’s first instruction is:

“He shall ask.”

When a believer falls, the first response should be prayer, not gossip.

Distinguish failure from apostasy

Peter denied Christ and returned.

The secessionists denied Christ and departed permanently.

A serious fall is not automatically final apostasy.

Do not terrorize tender consciences

A person who desires forgiveness and comes to Christ has not demonstrated final rejection of Him.

John 6:37

“Him that cometh to me I will in no wise cast out.”

Do not give false assurance to empty profession

Church membership, baptism, service, or a past prayer do not replace possession of the Son.

“He that hath the Son hath life.”

Take divine chastening seriously

Eternal security does not mean sin has no consequences.

God may discipline His children severely.

Leave final judgment to God

The church may judge doctrine and conduct.

It should be cautious about declaring that a living person has certainly committed the sin unto death.

Discussion Questions

Why is the context of 1 John 5:11–18 important for interpreting the sin unto death?
What does John normally mean by “life” and “death”?
Why are the secessionists of 1 John 2:19 important to the discussion?
How does verse 18 help explain verse 16?
What is the difference between Peter’s denial and final apostasy?
Why does the physical-death interpretation remain biblically possible?
What does 1 Corinthians 11 teach about divine chastening?
Why should Christians be cautious about identifying someone as beyond repentance?
What should be the church’s first response to a fallen brother?
How does this passage strengthen rather than weaken eternal security?

Key Verse

1 John 5:12

“He that hath the Son hath life; and he that hath not the Son of God hath not life.”

Key Truth

Life is in the Son. The sin unto death is deathward because it rejects the only One in whom eternal life is found.