I answer that, The precepts of the decalogue are differently divided by different authorities. For Hesychius commenting on Lev. 26:26, "Ten women shall bake your bread in one oven," says that the precept of the Sabbath-day observance is not one of the ten precepts, because its observance, in the letter, is not binding for all time. But he distinguishes four precepts pertaining to God, the first being, "I am the Lord thy God"; the second, "Thou shalt not have strange gods before Me," (thus also Jerome distinguishes these two precepts, in his commentary on Osee 10:10, "On thy" [Vulg.: "their"] "two iniquities"); the third precept according to him is, "Thou shalt not make to thyself any graven thing"; and the fourth, "Thou shalt not take the name of the Lord thy God in vain." He states that there are six precepts pertaining to our neighbor; the first, "Honor thy father and thy mother"; the second, "Thou shalt not kill"; the third, "Thou shalt not commit adultery"; the fourth, "Thou shalt not steal"; the fifth, "Thou shalt not bear false witness"; the sixth, "Thou shalt not covet."
But, in the first place, it seems unbecoming for the precept of the Sabbath-day observance to be put among the precepts of the decalogue, if it nowise belonged to the decalogue. Secondly, because, since it is written (Mt. 6:24), "No man can serve two masters," the two statements, "I am the Lord thy God," and, "Thou shalt not have strange gods before Me" seem to be of the same nature and to form one precept. Hence Origen (Hom. viii in Exod.) who also distinguishes four precepts as referring to God, unites these two under one precept; and reckons in the second place, "Thou shalt not make . . . any graven thing"; as third, "Thou shalt not take the name of the Lord thy God in vain"; and as fourth, "Remember that thou keep holy the Sabbath-day." The other six he reckons in the same way as Hesychius.
Since, however, the making of graven things or the likeness of anything is not forbidden except as to the point of their being worshipped as gods---for God commanded an image of the Seraphim [Vulg.: Cherubim] to be made and placed in the tabernacle, as related in Ex. 25:18---Augustine more fittingly unites these two, "Thou shalt not have strange gods before Me," and, "Thou shalt not make . . . any graven thing," into one precept. Likewise to covet another's wife, for the purpose of carnal knowledge, belongs to the concupiscence of the flesh; whereas, to covet other things, which are desired for the purpose of possession, belongs to the concupiscence of the eyes; wherefore Augustine reckons as distinct precepts, that which forbids the coveting of another's goods, and that which prohibits the coveting of another's wife. Thus he distinguishes three precepts as referring to God, and seven as referring to our neighbor. And this is better.