^13:8 Owe no one anything, except to love one another. For he who loves his neighbor has fulfilled the law. [n. 1044]
^13:9 For: you shall not commit adultery: you shall not kill: you shall not steal: you shall not bear false witness: you shall not covet. And if there be any other commandment, it is comprised in this word: you shall love your neighbor as yourself. [n. 1050]
^13:10 The love of our neighbor works no evil. Love therefore is the fulfillment of the law. [n. 1058]

1044. Having shown how believers should observe justice toward superiors, the Apostle now shows how they should behave toward everyone generally.

In regard to this he does two things:

first, he states his intention;

second, he gives a reason, at for he that loves.

1045. First, therefore, he says: it has been stated that you must pay your debts to all, not in part but entirely. And that is what he says: owe no one anything. As if to say: you should pay all you owe to everyone so completely that nothing still owing remains.

And this for two reasons: first, because sin is committed in delaying to pay, as long as a person unjustly holds back what belongs to another. Hence it says in Leviticus: the wages of a hired servant shall not remain with you all night until the morning (Lev 19:13). And the same is true of other debts.

Second, because as long as a person owes, he is in a certain sense a slave and is obligated to the one to whom he owes: the borrower is the slave of the lender (Prov 22:7).

1046. But there are some debts from which a man can never absolve himself. This happens in two ways: in one way on account of the excellence of the benefit for which equal payment cannot be made, as the Philosopher says of honor owed to God or parents, as it says in a psalm: what shall I render to the Lord for all his bounty to me? (Ps 116:12). In another way on account of the debt’s cause, which always remains; or even because what is paid is never terminated but always increases as one pays.

1047. For these reasons the debt of fraternal love is paid in such a way that it is always owing.

First, because we owe love to our neighbor on account of God, whom we can never recompense sufficiently. For it is said: this commandment we have from him, that he who loves God should love his brother also (1 John 4:2). Second, because the cause of love always remains, namely, being alike in nature and in grace: every animal loves its like, and every person his neighbor (Sir 13:15). Third, because love does not diminish but grows by loving: it is my prayer that your love may abound more and more (Phil 1:9).

Therefore, he says: except to love one another, because the debt of love is paid once in such a way that it always remains under the debt of a precept: this is my commandment, that you love one another (John 15:12).

1048. Then when he says, he who loves his neighbor, he assigns the reason for the statement that we are never released from the debt of love, namely, because the whole fulfillment of the law consists in love.

Hence he does three things in regard to this:

first, he states his proposition;

second, he clarifies it, at for you shall not commit adultery;

third, he draws the conclusion intended, at love therefore is the fulfillment of the law.

1049. First, therefore, he says: the reason why we cannot expect to free ourselves from the debt of love, as we do from other debts, is that for he who loves his neighbor has fulfilled the law, i.e., the whole fulfillment of the law depends on love of neighbor.

But this does not seem to be true. For it says in 1 Timothy: the end of the precept is love (1 Tim 1:5). For a thing is made perfect when it attains its end; therefore, the whole perfection of the law consists in love. But love has two acts, namely, the love of God and the love of neighbor; hence the Lord says in Matthew that the whole law and the prophets depend on the two precepts of love: one of which is concerned with the love of God and the other with the love of neighbor (Matt 22:40). Therefore, it does not seem that one who loves his neighbor fulfills the whole law.

The answer is that love of neighbor pertains to love and fulfills the law, when it is a love by which the neighbor is loved for God. So the love of God is included in the love of neighbor, just as the cause is included in its effect. For it says in 1 John: this commandment we have from him, that he who loves God should love his brother also (1 John 4:21). Conversely, love of neighbor is included in love of God, as the effect in its cause; hence it says in the same place: if anyone says, ‘I love God,’ and hates his brother, he is a liar.

That is why in Sacred Scripture sometimes mention is made only of the love of God, as though it is enough for salvation, as in Deuteronomy: and now, Israel, what does the Lord your God require of you, but to fear the Lord your God, to walk in all his ways, and to love him (Deut 10:12); and sometimes mention is made of love of neighbor: this is my commandment, that you love one another as I have loved you (John 15:12).

1050. Then when he says for you shall not commit adultery, he proves his proposition:

first, by induction;

second, by means of a syllogism, at the love of our neighbor.

1051. In regard to the first he proceeds inductively by enumerating certain precepts which fulfill the love of neighbor. And because the three precepts of the first tablet are more directly ordained to the love of God, he does not mention them, although they, too, are fulfilled in the love of neighbor, insofar as the love of God is included in the love of neighbor. But he enumerates the commands of the second tablet, omitting only the affirmative precept about honor to parents. By this it is understood that we should pay to all whatever we owe.

1052. He lists the negative precepts, which forbid a person to do evil to his neighbor. And this for two reasons.

First, because the negative precepts are more universal both as to time and as to persons. As to time, because the negative precepts oblige always and at every moment. For there is no time when one may steal or commit adultery. Affirmative precepts, on the other hand, oblige always but not at every moment, but at certain times and places: for a man is not obliged to honor his parents every minute of the day, but at certain times and places. Negative precepts are also more universal as to persons, because no man may be harmed, whereas we are not capable of each serving every other man.

Second, because they are more obviously observed by love of neighbor than are the affirmative. For a person who loves another, rather refrains from harming him than gives him benefits, which he is sometimes unable to give.

1053. But a person does injury to his neighbor in three ways: by action, by word, and by desire.

He does injury by action in three ways: first, against the neighbor’s person, and this is forbidden when he says: you shall not kill. This also forbids any injury against the neighbor’s person: no murderer has eternal life abiding in him (1 John 3:15).

Second, against a person’s wife; and this is forbidden when he says: you shall not commit adultery. This also forbids fornication and any unlawful use of the genital organs: God will judge fornicators and adulterers (Heb 13:4).

Third, against one’s external goods, and this is forbidden when he says: you shall not steal. This also forbids any unjust taking of what belongs to another, either by force or by deceit: everyone who steals will be judged (Zech 5:3).

1054. Injury committed by word against one’s neighbor is forbidden when he says: you shall not bear false witness. This is forbidden not only in court cases but also outside, whether in the form of detraction or of insults: the false witness will not go unpunished, and one who speaks lies will not escape (Prov 19:5).

Injury committed only by desire against one’s neighbor is forbidden when he says: you shall not covet your neighbor’s good; and this also forbids coveting another’s wife: for I would not have known covetousness to be a sin, if the law had not said: you shall not covet (Rom 7:7).

1055. These commandments are set forth in Exodus 20:17 et seq. Having listed a number of precepts, he combines all others in one general precept, saying: and if there be any other commandment, affirmative or negative, referring to God or to neighbor, it is comprised, i.e., fulfilled, in this word: you shall love your neighbor as yourself. This is said in Leviticus, where our text has: you shall love your friend as yourself (Lev 19:18).

1056. When he says, your neighbor, the reference is to all men and also the good angels, as Augustine says. For a neighbor is anyone who shows mercy to another, as it says in Luke: which of these three, do you think, proved neighbor to the man who fell among robbers? He said: the one who showed mercy to him (Luke 10:36). And because a neighbor is neighbor to a neighbor, the consequence is that even a person shown mercy by another is said to be his neighbor. But the good angels show mercy to us; and we should show mercy to all men and receive it from them, when necessary. Hence it is clear that the good angels and all men are our neighbors, because the happiness toward which we are tending is already theirs, or they are tending toward it with us.

From this reason it is clear that devils are not our neighbors and that we are not commanded to love them, because they are entirely excluded from the love of God and are not included in the list of neighbors but of enemies.

1057. The phrase, as yourself, does not refer to equality of love, as though a person were bound to love his neighbor as much as himself. For this would be against the ordering of charity, by which a person is obliged to take more care of his own salvation than that of others: he put love in order in me (Song 2:4). It refers, rather to a similarity of love, namely, that we should love our neighbor similarly as ourselves.

And this in three ways: first, as to the end of love, namely, that we love ourselves and our neighbor for the sake of God. Second, as to the form of love, namely, just as a person loves himself as willing good for himself, so he should love his neighbor by willing good things for him. But one who loves his neighbor in order to acquire some utility or love from him does not will good for his neighbor but wants to obtain a good for himself from his neighbor. This is the way a man is said to love irrational creatures, such as wine or a horse, namely, to use them. Third, as to the effect of love, namely, that he relieve the need of his neighbor, as he relieves his own; and that he do nothing unlawful out of love for his neighbor any more than he does out of love for himself.

1058. Then when he says, the love of our neighbor works no evil, he clarifies his proposition with the following syllogism: One who loves his neighbor does no evil to him. But the aim of every precept of the law is abstention from evil. Therefore, one who loves his neighbor fulfills the law. That love of neighbor does no evil is gathered from 1 Corinthians: love does not work injury (1 Cor 13:4).

No matter how evil is taken here, whether for evil acts or omissions, it could refer not only to negative precepts but also to affirmative. But inasmuch as love of neighbor includes love of God, it is understood that love of neighbor excludes evil both against one’s neighbor and against God. Thus, even the precepts of the first tablet are included.

1059. Finally, he draws the conclusion mainly intended, saying: therefore, love is the fulfillment of the law, i.e., the law is fulfilled and made perfect by love. My abode is in the full assembly of the saints (Sir 14:16); above all these put on love, which binds everything together in perfect harmony (Col 3:14).