73 But the question before us is rendered more urgent by what the Apostle John says: “If any man see his brother sin a sin which is not unto death, he shall ask, and the Lord shall give him life for him who sins not unto death. There is a sin unto death: I do not say that he shall pray for it.” For he manifestly shows that there are certain brethren for whom we are not commanded to pray, although the Lord bids us pray even for our persecutors. Nor can the question in hand be solved, unless we acknowledge that there are certain sins in brethren which are more heinous than the persecution of enemies. Moreover, that brethren mean Christians can be proved by many examples from the divine Scriptures. Yet that one is plainest which the apostle thus states: “For the unbelieving husband is sanctified in the wife, and the unbelieving wife is sanctified in the brother.” For he has not added the word our; but has thought it plain, as he wished a Christian who had an unbelieving wife to be understood by the expression brother. And therefore he says a little after, “But if the unbelieving depart, let him depart: a brother or a sister is not under bondage in such cases.” Hence I am of opinion that the sin of a brother is unto death, when any one, after coming to the knowledge of God through the grace of our Lord Jesus Christ, makes an assault on the brotherhood, and is impelled by the fires of envy to oppose that grace itself by which he is reconciled to God. But the sin is not unto death, if any one has not withdrawn his love from a brother, but through some infirmity of disposition has failed to perform the incumbent duties of brotherhood. And on this account our Lord also on the cross says, “Father, forgive them; for they know not what they do:” for, not yet having become partakers of the grace of the Holy Spirit, they had not yet entered the fellowship of the holy brotherhood. And the blessed Stephen in the Acts of the Apostles prays for those by whom he is being stoned, because they had not yet believed on Christ, and were not fighting against that common grace. And the Apostle Paul on this account, I believe, does not pray for Alexander, because he was already a brother, and had sinned unto death, viz. by making an assault on the brotherhood through envy. But for those who had not broken off their love, but had given way through fear, he prays that they may be pardoned. For thus he expresses it: “Alexander the coppersmith did me much evil: the Lord will reward him according to his works. Of whom also beware; for he has greatly withstood our words.” Then he adds for whom he prays, thus expressing it: “At my first defence no man stood with me, but all men forsook me: I pray God that it may not be laid to their charge.”
74. It is this difference in their sins which separates Judas the betrayer from Peter the denier: not that a penitent is not to be pardoned, for we must not come into collision with that declaration of our Lord, where He enjoins that a brother is to be pardoned, when he asks his brother to pardon him; but that the ruin connected with that sin is so great, that he cannot endure the humiliation of asking for it, even if he should be compelled by a bad conscience both to acknowledge and divulge his sin. For when Judas had said, “I have sinned, in that I have betrayed the innocent blood,” yet it was easier for him in despair to run and hang himself, than in humility to ask for pardon. And therefore it is of much consequence to know what sort of repentance God pardons. For many much more readily confess that they have sinned, and are so angry with themselves that they vehemently wish they had not sinned; but yet they do not condescend to humble the heart and to make it contrite, and to implore pardon: and this disposition of mind we must suppose them to have, as feeling themselves already condemned because of the greatness of their sin.
75. And this is perhaps the sin against the Holy Ghost, i.e. through malice and envy to act in opposition to brotherly love after receiving the grace of the Holy Ghost—a sin which our Lord says is not forgiven either in this world or in the world to come. And hence it may be asked whether the Jews sinned against the Holy Ghost, when they said that our Lord was casting out devils by Beelzebub, the prince of the devils: whether we are to understand this as said against our Lord Himself, because He says of Himself in another passage, “If they have called the Master of the house Beelzebub, how much more shall they call them of His household!” or whether, inasmuch as they had spoken from great envy, being ungrateful for so manifest benefits, although they were not yet Christians, they are, from the very greatness of their envy, to be supposed to have sinned against the Holy Ghost? This latter is certainly not to be gathered from our Lord's words. For although He has said in the same passage, “And whosoever speaks a word against the Son of man, it shall be forgiven him; but whosoever speaks a word against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come;” yet it may seem that He admonished them for this purpose, that they should come to His grace, and after accepting of it should not so sin as they have now sinned. For now they have spoken a word against the Son of man, and it may be forgiven them, if they be converted, and believe in Him, and receive the Holy Ghost; but if, after receiving Him, they should choose to envy the brotherhood, and to assail the grace they have received, it cannot be forgiven them, neither in this world nor in the world to come. For if He reckoned them so condemned, that there was no hope left for them, He would not judge that they ought still to be admonished, as He did by adding the statement, “Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt.”
76. Let it be understood, therefore, that we are to love our enemies, and to do good to those who hate us, and to pray for those who persecute us, in such a way, that it is at the same time understood that there are certain sins of brethren for which we are not commanded to pray; lest, through unskilfulness on our part, divine Scripture should seem to contradict itself (a thing which cannot happen). But whether, as we are not to pray for certain parties, so we are also to pray against some, has not yet become sufficiently evident. For it is said in general, “Bless, and curse not;” and again, “Recompense to no man evil for evil.” Moreover, while you do not pray for one, you do not therefore pray against him: for you may see that his punishment is certain, and his salvation altogether hopeless; and you do not pray for him, not because you hate him, but because you feel you can profit him nothing, and you do not wish your prayer to be rejected by the most righteous Judge. But what are we to think respecting those parties against whom we have it revealed that prayers were offered by the saints, not that they might be turned from their error (for in this way prayer is offered rather for them), but that final condemnation might come upon them: not as it was offered against the betrayer of our Lord by the prophet; for that, as has been said, was a prediction of things to come, not a wish for punishment: nor as it was offered by the apostle against Alexander; for respecting that also enough has been already said: but as we read in the Apocalypse of John of the martyrs praying that they may be avenged; while the well-known first martyr prayed that those who stoned him should be pardoned.
Source: Our Lord's Sermon on the Mount (New Advent)