16 If these things be so, how shall a man who shall keep the whole law, and yet offend in one point, be guilty of all? May it not be, that since the fulfilling of the law is that love wherewith we love God and our neighbour, on which commandments of love “hang all the law and the prophets,” he is justly held to be guilty of all who violates that on which all hang? Now, no one sins without violating this love; “for this, you shall not commit adultery; you shall do no murder; you shall not steal; you shall not covet; and if there be any other commandment, it is briefly comprehended in this saying, You shall love your neighbour as yourself. Love works no ill to his neighbour: therefore love is the fulfilling of the law.” No one, however, loves his neighbour who does not out of his love to God do all in his power to bring his neighbour also, whom he loves as himself, to love God, whom if he does not love, he neither loves himself nor his neighbour. Hence it is true that if a man shall keep the whole law, and yet offend in one point, he becomes guilty of all, because he does what is contrary to the love on which hangs the whole law. A man, therefore, becomes guilty of all by doing what is contrary to that on which all hang.
17. Why, then, may not all sins be said to be equal? May not the reason be, that the transgression of the law of love is greater in him who commits a more grievous sin, and is less in him who commits a less grievous sin? And in the mere fact of his committing any sin whatever, he becomes guilty of all; but in committing a more grievous sin, or in sinning in more respects than one, he becomes more guilty; committing a less grievous sin, or sinning in fewer respects, he becomes less guilty—his guilt being thus so much the greater the more he has sinned, the less the less he has sinned. Nevertheless, even though it be only in one point that he offend, he is guilty of all, because he violates that love on which all hang. If these things be true, an explanation is by this means found, clearing up that saying of the man of apostolic grace, “In many things we offend all.” For we all offend, but one more grievously, another more slightly, according as each may have committed a more grievous or a less grievous sin; every one being great in the practice of sin in proportion as he is deficient in loving God and his neighbour, and, on the other hand, decreasing in the practice of sin in proportion as he increases in the love of God and of his neighbour. The more, therefore, that a man is deficient in love, the more is he full of sin. And perfection in love is reached when nothing of sinful infirmity remains in us.
18. Nor, indeed, in my opinion, are we to esteem it a trifling sin “to have the faith of our Lord Jesus Christ with respect of persons,” if we take the difference between sitting and standing, of which mention is made in the context, to refer to ecclesiastical honours; for who can bear to see a rich man chosen to a place of honour in the Church, while a poor man, of superior qualifications and of greater holiness, is despised? If, however, the apostle speaks there of our daily assemblies, who does not offend in the matter? At the same time, only those really offend here who cherish in their hearts the opinion that a man's worth is to be estimated according to his wealth; for this seems to be the meaning of the expression, “Are ye not then partial in yourselves, and have become judges of evil thoughts?”
19. The law of liberty, therefore, the law of love, is that of which he says: If you fulfil the royal law according to the Scripture, You shall love your neighbour as yourself, you do well: but if you have respect to persons, you commit sin, and are convinced of the law as transgressors. And then (after the difficult sentence, “Whosoever shall keep the whole law, and yet offend in one point, he is guilty of all,” concerning which I have with sufficient fullness stated my opinion), making mention of the same law of liberty, he says: “So speak ye, and so do, as they that shall be judged by the law of liberty.” And as he knew by experience what he had said a little before, “in many things we offend all,” he suggests a sovereign remedy, to be applied, as it were day by day, to those less serious but real wounds which the soul suffers day by day, for he says: “He shall have judgment without mercy that has showed no mercy.” For with the same purpose the Lord says: “Forgive, and you shall be forgiven: give, and it shall be given unto you.” After which the apostle says: “But mercy rejoices over judgment:” it is not said that mercy prevails over judgment, for it is not an adversary of judgment, but it “rejoices” over judgment, because a greater number are gathered in by mercy; but they are those who have shown mercy, for, “Blessed are the merciful, for God shall have mercy on them.”
20. It is, therefore, by all means just that they be forgiven, because they have forgiven others, and that what they need be given to them, because they have given to others. For God uses mercy when He judges, and uses judgment when He shows mercy. Hence the Psalmist says: “I will sing of mercy and of judgment unto You, O Lord.” For if any man, thinking himself too righteous to require mercy, presumes, as if he had no reason for anxiety, to wait for judgment without mercy, he provokes that most righteous indignation through fear of which the Psalmist said: “Enter not into judgment with Your servant.” For this reason the Lord says to a disobedient people: Wherefore will you contend with me in judgment? For when the righteous King shall sit upon His throne, who shall boast that he has a pure heart, or who shall boast that he is clean from sin? What hope is there then unless mercy shall “rejoice over” judgment? But this it will do only in the case of those who have showed mercy, saying with sincerity, “Forgive us our debts, as we forgive our debtors,” and who have given without murmuring, for “the Lord loves a cheerful giver.” To conclude, St. James is led to speak thus concerning works of mercy in this passage, in order that he may console those whom the statements immediately foregoing might have greatly alarmed, his purpose being to admonish us how those daily sins from which our life is never free here below may also be expiated by daily remedies; lest any man, becoming guilty of all when he offends in even one point, be brought, by offending in many points (since “in many things we all offend”), to appear before the bar of the Supreme Judge under the enormous amount of guilt which has accumulated by degrees, and find at that tribunal no mercy, because he showed no mercy to others, instead of rather meriting the forgiveness of his own sins, and the enjoyment of the gifts promised in Scripture, by his extending forgiveness and bounty to others.
Source: Letters (New Advent)