The interpretation timeline

1John 5:16

How this passage has been read — the sources, oldest to newest.

From the early Church Fathers to now.

17 Patristic · 1 Orthodox

1John 5:16 · Douay-Rheims
“He that knoweth his brother to sin a sin which is not to death, let him ask, and life shall be given to him, who sinneth not to death. There is a sin unto death: for that I say not that any man ask.”
Patristic before A.D. 750
215
A.D.
Clement of Alexandria Patristic
c. A.D. 150–215
“John, too, manifestly teaches the differences of sins, in his larger Epistle, in these words: "If any man see his brother sin a sin that is not unto death, he shall ask, and he shall give him life: for these that sin not unto death," he says. For "there is a sin unto death: I do not say that one is to pray for it. All unrighteousness is sin; and there is a sin not unto death."”
Source
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“Touching this difference, we have not only already premised certain antithetical passages of the Scriptures, on one hand retaining, on the other remitting, sins; but John, too, will teach us: "If any knoweth his brother to be sinning a sin not unto death, he shall request, and life shall be given to him; "because he is not "sinning unto death," this will be remissible. "(There) is a sin unto death; not for this do I say that any is to request" -this will be irremissible.”
Source
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“For (in making these assertions) he was looking forward to the final clause of his letter, and for that (final clause) he was laying his preliminary bases; intending to say, in the end, more manifestly: "If any knoweth his brother to be sinning a sin not unto death, he shall make request, and the Lord shall give life to him who sinneth not unto death. For there is a sin unto death: not concerning that do I say that one should make request." He, too, (as I have been), was mindful that Jeremiah had been prohibited by God to deprecate (Him) on behalf of a people which was committing mortal sins.”
Source
254
A.D.
Origen Patristic
c. A.D. 184–253
“Since there are sins "unto death," it follows that anyone who commits one of them will die as a result.”
258
A.D.
Cyprian Patristic
c. A.D. 200–258
“That remission cannot in the Church be granted unto him who has sinned against God (i.e., the Holy Ghost): In the Gospel according to Matthew: "Whosoever shall say a word against the Son of man, it shall be forgiven him; but whosoever shall speak against the Holy Ghost, it shall not be forgiven him, neither in this world nor in the world to come." Also according to Mark: "All sins shall be forgiven, and blasphemies, to the sons of men; but whoever shall blaspheme against the Holy Ghost, it shall not be forgiven him, but he shall be guilty of eternal sin." Of this same thing in the first book of Kings: "If a man sin by offending against a man, they shall pray the Lord for him; but if a man sin against God, who shall pray for him?"”
Source
172 years pass — nothing from this stretch is hosted yet
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“For it manifestly shows that there are some "brethren" whom we are not commanded to pray for, whereas the Lord bids us pray even for our persecutors. Nor can this question be solved except we acknowledge, that there are some sins in brethren that are worse than the sin of enemies in persecuting. The "sin," therefore, of a brother, "unto death," I suppose to be when, after the acknowledging of God through the grace of our Lord Jesus Christ, one fights against the brotherhood, and is set on by the fire-brands of hatred against the very grace through which he was reconciled to God.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“In another place I defined the sin of a brother unto death [see above], but I should have added: "if he ends this life in a perversity of mind as wicked as this." For surely we must not despair of anyone, no matter how wicked he is, while he lives, and we should pray with confidence for him of whom we should not despair.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“But what presses harder upon the present question is that saying of the apostle John, "If any man know that his brother sinneth a sin not unto death, he shall ask, and the Lord will give life to that man who sinneth not unto death: but there is a sin unto death: not for that do I say that he should ask." For it manifestly shows that there are some "brethren" whom we are not commanded to pray for, whereas the Lord bids us pray even for our persecutors. Nor can this question be solved except we acknowledge, that there are some sins in brethren that are worse than the sin of enemies in persecuting.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“The "sin," therefore, of a brother, "unto death," I suppose to be when, after the acknowledging of God through the grace of our Lord Jesus Christ, one fights against the brotherhood, and is set on by the fire-brands of hatred against the very grace through which he was reconciled to God. But "a sin not unto death" is when a person, not having alienated his love from his brother, yet through some infirmity of mind may have failed to exhibit the due offices of brotherhood. Wherefore, on the one hand, the Lord on the cross said, "Father, forgive them, for they know not what they do," since they had not yet, by being made partakers of the grace of the Holy Spirit, entered into the fellowship of holy brotherhood; and blessed Stephen in the Acts of the Apostles prays for them who are stoning him; because they had not yet believed Christ, and were not fighting against that grace of communion. On the other hand, the apostle Paul does not pray for Alexander, and the reason I suppose, is, that this man was a brother, and had sinned "unto death," i.e. by opposing the brotherhood in a spirit of hatred. Whereas for such as had not broken off the bonds of love, but had given way through fear, he prays that they may be forgiven. For so he says: "Alexander the coppersmith did me much evil: the Lord reward him according to his works: of whom be thou ware also; for he hath greatly withstood our words." Then he subjoins for whom he prays, saying, "At my first answer no man stood with me, but all men forsook me: I pray God that it may not be laid to their charge."”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“This difference of sins it is that distinguishes Judas with his treason from Peter with his denial. Not that to him who repenteth there is to be no forgiveness: lest we go against that sentence of the Lord, in which He commands always to forgive the brother who asks his brother's forgiveness: but that the mischief of that sin is, that the man cannot submit to the humiliation of begging for pardon, even when he is forced by his evil conscience both to acknowledge and to publish his sin. For when Judas had said, "I have sinned, in that I have betrayed the innocent blood," he went and hanged himself in desperation, rather than pray for forgiveness in humiliation. Wherefore it makes a great difference, what sort of repentance God forgives. For many are much quicker than others to confess that they have sinned, and are angry with themselves in such sort that they vehemently wish they had not sinned, while yet they cannot lay down their pride, and submit to have the heart humbled and broken so as to implore pardon: a state of mind which one may well believe to be, for the greatness of their sin, a part of their already begun damnation.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“And this, perhaps, it is "to sin against the Holy Ghost:" i.e. through malice and envy to fight against brotherly charity after receiving the grace of the Holy Spirit: that sin which the Lord saith hath no forgiveness, either here or in the world to come. For the Lord in saying to the Pharisees, "Whosoever shall speak an evil word against the Son of Man," may have meant to warn them to come to the grace of God, and having received it, not to sin as they have now sinned. For now they have spoken an evil word against the Son of Man, and it may be forgiven them, if they be converted and believe and receive the Holy Spirit: which when they have received, if they will then have ill-will against the brotherhood and oppose the grace they have received, there is no forgiveness for them, either in this world or in the world to come.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“By this grace such is the liberty they receive, that although as long as they live here they have to fight against the lusts of sins, and are overtaken by some sins for which they must daily pray, "Forgive us our debts," yet they no longer serve the sin which is unto death, of which the apostle John saith, "There is a sin unto death, I do not say that he shall ask for that." Concerning which sin (since it is not expressed) many different opinions may be formed: but I affirm that sin to be the forsaking until death the "faith which worketh by love."”
Source
207 years pass — nothing from this stretch is hosted yet
637
A.D.
Andreas of Caesarea Patristic
c. A.D. 563–637
“It is the sin of heresy, or of blasphemy against the Holy Spirit, which leads to death. If one man sins against another, pray for him. But if he sins against God, who is there who can pray on his behalf?”
735
A.D.
Bede Patristic
A.D. 673–735
“Just as Christ washes us from our sins by interceding with the Father on our behalf, so also should we, if we know that our brother is committing a sin which is "not unto death."”
735
A.D.
Bede Patristic
A.D. 673–735
“Who knows his brother to sin a sin not unto death, etc. These and such things are asked according to the will of the Lord, which pertain to the duty of brotherly love. He speaks, however, of daily and light sins, which as they are difficult to avoid, so also are easily cured. But regarding the manner in which this mutual request should be carried out for sins, James more clearly indicates, saying: Confess your sins to one another, and pray for one another that you may be saved (James V). If, therefore, by speaking, or thinking, or forgetfulness, or ignorance you have perhaps erred, go to your brother, confess to him, ask for intervention. If he purely confesses to you, making you aware of his own frailty, and you piously intercede for his errors, correct him. But these things are said about lighter sins. Moreover, if you have committed something more serious, bring in the elders of the Church, and at their examination, punish yourself.”
Source
735
A.D.
Bede Patristic
A.D. 673–735
“There is a sin unto death, etc. A great question arises here, because blessed John clearly shows that there are certain brothers for whom we are not instructed to pray, whereas the Lord even commands us to pray for our persecutors. This can only be resolved by admitting that there are some sins among the brothers which are more grievous than the persecution by enemies. Therefore, the sin of a brother unto death occurs when, after the knowledge of God, which is given through the grace of our Lord Jesus Christ, someone attacks the brotherhood and is inflamed with envy against the very grace by which they were reconciled to God. However, a sin not unto death is if someone has not withdrawn love from their brother but has not shown the duties owed to brotherhood due to some weakness of mind. Therefore, the Lord on the cross says: Father, forgive them, for they do not know what they are doing (Luke 23). For they had not yet become participants in the grace of the Holy Spirit, nor had they entered the communion of holy brotherhood. And blessed Stephen prays for those by whom he was being stoned because they did not yet believe in Christ, nor did they fight against that common grace. And the apostle Paul, for this reason, I believe, does not pray for Alexander because he was already a brother; and he had sinned unto death, that is, by attacking brotherhood with envy. But he prays that those who had not severed love but had succumbed to fear be forgiven. For he thus says: Alexander the coppersmith did me much evil; the Lord will repay him according to his works; whom do you also avoid, for he has greatly resisted our words (2 Tim. 4). Then he adds for whom he prays, saying: At my first defense, no one stood with me, but all forsook me; may it not be charged against them (Ibid.). However, a sin unto death can be understood as one for which someone is forbidden to pray, because a sin that is not corrected in this life, its forgiveness is sought in vain after death. But if we carefully inspect the following, the previous sense of this reading seems to align more with its tenor. For it continues:”
Source
391 years pass — nothing from this stretch is hosted yet
Scholastic c. 1100 – 1500
1126
A.D.
Theophylact of Ohrid Orthodox
c. 1055–1107
“Having said that God fulfills our requests that are in accordance with His will, the apostle now clearly expresses his desire concerning what we should ask for according to God's will. And since he spoke much, almost throughout the entire epistle, about love for one's brother and about the fact that God desires that we maintain love for our brother without hypocrisy, he now names as one of His desires, and the very best one, that when someone sees his brother sinning a sin that is not mortal, let him ask, and He will give him. What will He give? Eternal life. To whom? To those sinning not unto death. In general, he divides sin thus: all unrighteousness is sin, and one sin is unto death, another is not unto death. But concerning the sin unto death he says: let him not ask, that is, let him not pray, for he will not be heard, because he asks not for what is good. He means the one who shows no sign of repentance. For the sin unto death is precisely that in which no repentance is offered. Judas was afflicted with this sin, and was subjected to eternal death. Those who bear grudges also sin unto death, for Solomon says: "the ways of those who remember evil lead to death" (Prov. 12:28). For those who remember evil and do not cease their anger against their neighbor do not turn to repentance, but sin unforgivably.”
Source
Undated date unknown
Oecumenius Patristic
c. A.D. 550
“If anyone sees his brother sinning a sin not leading 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. All unrighteousness is sin, and there is sin not leading to death. "If anyone sees his brother sinning." This is one will. For it is righteous to feel compassion for the brother who has sinned and to be of help for salvation. "There is a sin leading to death." Let this be the order: There is a sin that leads to death, and there is a sin that does not lead to death. I do not say that one should pray for the one that leads to death, but for the one that does not lead to death. Then he explains the distinction making between the sin that leads to death and the one that does not lead to death. For John simply divides it as a kind of sin and says: All unrighteousness is sin: whether it leads to death or does not lead to death. But because it is unto death, let him not pray or ask, for he will not be heard because he asks with wrong motives (James 4:3), especially when he shows no sign of conversion. For this alone is the sin that leads death, which does not regard repentance: when Judas fell ill with this, he was taken to eternal death. And those also sin that leads death who are mindful of injuries. For the paths of those who remember injuries lead to death (Prov. 12:28 LXX.), says Solomon. Nor do they convert by remembering, retaining the memory of injuries, and keeping anger against their neighbor, but they sin without repentance.”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.