Reply Obj. 2:  As the Apostle says (1 Tim. 1:5), “the end of the commandment is charity”; since every law aims at establishing friendship, either between man and man, or between man and God.  Wherefore the whole Law is comprised in this one commandment, “Thou shalt love thy neighbor as thyself,” as expressing the end of all commandments:  because love of one’s neighbor includes love of God, when we love our neighbor for God’s sake.  Hence the Apostle put this commandment in place of the two which are about the love of God and of one’s neighbor, and of which Our Lord said (Matt. 22:40):  “On these two commandments dependeth the whole Law and the prophets.”

Reply Obj. 3:  As stated in Ethic. ix, 8, “friendship towards another arises from friendship towards oneself,” in so far as man looks on another as on himself.  Hence when it is said, “All things whatsoever you would that men should do to you, do you also to them,” this is an explanation of the rule of neighborly love contained implicitly in the words, “Thou shalt love thy neighbor as thyself”:  so that it is an explanation of this commandment. ________________________

SECOND ARTICLE [I-II, Q. 99, Art. 2]

Whether the Old Law Contains Moral Precepts?

Objection 1:  It would seem that the Old Law contains no moral precepts.  For the Old Law is distinct from the law of nature, as stated above (Q. 91, AA. 4, 5; Q. 98, A. 5).  But the moral precepts belong to the law of nature.  Therefore they do not belong to the Old Law.

Obj. 2:  Further, the Divine Law should have come to man’s assistance where human reason fails him:  as is evident in regard to things that are of faith, which are above reason.  But man’s reason seems to suffice for the moral precepts.  Therefore the moral precepts do not belong to the Old Law, which is a Divine law.

Obj. 3:  Further, the Old Law is said to be “the letter that killeth” (2 Cor. 3:6).  But the moral precepts do not kill, but quicken, according to Ps. 118:93:  “Thy justifications I will never forget, for by them Thou hast given me life.”  Therefore the moral precepts do not belong to the Old Law.

On the contrary, It is written (Ecclus. 17:9):  “Moreover, He gave them discipline [Douay:  ‘instructions’] and the law of life for an inheritance.”  Now discipline belongs to morals; for this gloss on Heb. 12:11:  “Now all chastisement (disciplina),” etc., says:  “Discipline is an exercise in morals by means of difficulties.”  Therefore the Law which was given by God comprised moral precepts.

I answer that, The Old Law contained some moral precepts; as is evident from Ex. 20:13, 15:  “Thou shalt not kill,” “Thou shalt not steal.”  This was reasonable:  because, just as the principal intention of human law is to create friendship between man and man; so the chief intention of the Divine law is to establish man in friendship with God.  Now since likeness is the reason of love, according