Section II: On the Individual Precepts of the Decalogue

528. The DECALOGUE comprises TEN precepts. The ORDER of these precepts is thus explained according to the mind of St. Thomas (1.2, q. 100, a. 5): Just as the precepts of human law order man to a certain human community, so the precepts of divine law order man to a certain community under God. But for someone to dwell well in some community, TWO things are required: the first of which is that he conduct himself well toward him who presides over the community; but the other is that he conduct himself well toward the other consociates and co-participants of the community. Whence the Decalogue contains precepts ordering man to God and to neighbors.

To GOD, the PRINCE of the community, three things are owed: fidelity, reverence, service. FIDELITY is owed, so that the honor of principality is not carried to another: therefore first it is said: Thou shalt not have strange gods. REVERENCE is required, so that nothing injurious is committed against him; whence the second precept: Thou shalt not take the name of the Lord thy God in vain. SERVICE is prescribed in recompense for benefits, especially the creation of the world; and to this pertains the third precept concerning sanctification of the Sabbath.

But toward NEIGHBORS someone conducts himself well both specially and generally. SPECIALLY indeed as regards those of whom he is a debtor; whence the fourth precept concerning honoring parents. - But GENERALLY as regards all, so that harm is inflicted upon no one, neither by deed, nor by mouth, nor by heart. By DEED indeed harm is inflicted upon neighbors, sometimes upon one's own person, as regards the consistency of the person, and this is prohibited by the words: Thou shalt not kill; sometimes upon a conjoined person, as regards propagation of offspring, whence it is said: Thou shalt not commit adultery; sometimes upon a thing possessed, therefore it is said: Thou shalt not steal. But harm of the MOUTH is prohibited when it is said: Thou shalt not speak false testimony against thy neighbor. But harm of the HEART is prohibited when it is said: Thou shalt not covet.

From these things you conclude: 1. No precepts are posited which directly order man TO HIMSELF. The reason for this omission, according to St. Thomas (l. c., ad 1), is that love of oneself is included in love of God and neighbor. Cf. the things said above n. 476.

2. All precepts of the Decalogue pertain TO JUSTICE and to the virtues annexed to justice, namely, the first three precepts refer themselves to RELIGION, the fourth to PIETY, and the rest to COMMUTATIVE JUSTICE (ibid., a. 11, ad 3).

These things having been premised, let us treat in order concerning the individual precepts.