Reply Obj. 2:  All the solemnities of the Old Law were instituted in celebration of some Divine favor, either in memory of past favors, or in sign of some favor to come:  in like manner all the sacrifices were offered up with the same purpose.  Now of all the Divine favors to be commemorated the chief was that of the Creation, which was called to mind by the sanctification of the Sabbath; wherefore the reason for this precept is given in Ex. 20:11:  “In six days the Lord made heaven and earth,” etc.  And of all future blessings, the chief and final was the repose of the mind in God, either, in the present life, by grace, or, in the future life, by glory; which repose was also foreshadowed in the Sabbath-day observance:  wherefore it is written (Isa. 58:13):  “If thou turn away thy foot from the Sabbath, from doing thy own will in My holy day, and call the Sabbath delightful, and the holy of the Lord glorious.”  Because these favors first and chiefly are borne in mind by men, especially by the faithful.  But other solemnities were celebrated on account of certain particular favors temporal and transitory, such as the celebration of the Passover in memory of the past favor of the delivery from Egypt, and as a sign of the future Passion of Christ, which though temporal and transitory, brought us to the repose of the spiritual Sabbath.  Consequently, the Sabbath alone, and none of the other solemnities and sacrifices, is mentioned in the precepts of the decalogue.

Reply Obj. 3:  As the Apostle says (Heb. 6:16), “men swear by one greater than themselves; and an oath for confirmation is the end of all their controversy.”  Hence, since oaths are common to all, inordinate swearing is the matter of a special prohibition by a precept of the decalogue.  According to one interpretation, however, the words, “Thou shalt not take the name of the Lord thy God in vain,” are a prohibition of false doctrine, for one gloss expounds them thus:  “Thou shalt not say that Christ is a creature.”

Reply Obj. 4:  That a man should not do harm to anyone is an immediate dictate of his natural reason:  and therefore the precepts that forbid the doing of harm are binding on all men.  But it is not an immediate dictate of natural reason that a man should do one thing in return for another, unless he happen to be indebted to someone.  Now a son’s debt to his father is so evident that one cannot get away from it by denying it:  since the father is the principle of generation and being, and also of upbringing and teaching.  Wherefore the decalogue does not prescribe deeds of kindness or service to be done to anyone except to one’s parents.  On the other hand parents do not seem to be indebted to their children for any favors received, but rather the reverse is the case.  Again, a child is a part of his father; and “parents love their children as being a part of themselves,” as the Philosopher states (Ethic. viii, 12).  Hence, just as the decalogue contains no ordinance as to man’s behavior towards himself, so, for the same reason, it includes no precept about loving one’s children.