Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that there is but one Divine law. Because, where there is one king in one kingdom there is but one law. Now the whole of mankind is compared to God as to one king, according to Ps. 46:8: "God is the King of all the earth." Therefore there is but one Divine law.

Objection 2: Further, every law is directed to the end which the lawgiver intends for those for whom he makes the law. But God intends one and the same thing for all men; since according to 1 Tim. 2:4: "He will have all men to be saved, and to come to the knowledge of the truth." Therefore there is but one Divine law.

Objection 3: Further, the Divine law seems to be more akin to the eternal law, which is one, than the natural law, according as the revelation of grace is of a higher order than natural knowledge. Therefore much more is the Divine law but one.

On the contrary, The Apostle says (Heb. 7:12): "The priesthood being translated, it is necessary that a translation also be made of the law." But the priesthood is twofold, as stated in the same passage, viz. the levitical priesthood, and the priesthood of Christ. Therefore the Divine law is twofold, namely the Old Law and the New Law.

I answer that, As stated in the 1, Question 30, Article 3, distinction is the cause of number. Now things may be distinguished in two ways. First, as those things that are altogether specifically different, e.g. a horse and an ox. Secondly, as perfect and imperfect in the same species, e.g. a boy and a man: and in this way the Divine law is divided into Old and New. Hence the Apostle (Gal. 3:24,25) compares the state of man under the Old Law to that of a child "under a pedagogue"; but the state under the New Law, to that of a full grown man, who is "no longer under a pedagogue."

Now the perfection and imperfection of these two laws is to be taken in connection with the three conditions pertaining to law, as stated above. For, in the first place, it belongs to law to be directed to the common good as to its end, as stated above (Question 90, Article 2). This good may be twofold. It may be a sensible and earthly good; and to this, man was directly ordained by the Old Law: wherefore, at the very outset of the law, the people were invited to the earthly kingdom of the Chananaeans (Ex. 3:8,17). Again it may be an intelligible and heavenly good: and to this, man is ordained by the New Law. Wherefore, at the very beginning of His preaching, Christ invited men to the kingdom of heaven, saying (Mt. 4:17): "Do penance, for the kingdom of heaven is at hand." Hence Augustine says (Contra Faust. iv) that "promises of temporal goods are contained in the Old Testament, for which reason it is called old; but the promise of eternal life belongs to the New Testament."

Secondly, it belongs to the law to direct human acts according to the order of righteousness (Article 4): wherein also the New Law surpasses the Old Law, since it directs our internal acts, according to Mt. 5:20: "Unless your justice abound more than that of the Scribes and Pharisees, you shall not enter into the kingdom of heaven." Hence the saying that "the Old Law restrains the hand, but the New Law controls the mind" ( Sentent. iii, D, xl).

Thirdly, it belongs to the law to induce men to observe its commandments. This the Old Law did by the fear of punishment: but the New Law, by love, which is poured into our hearts by the grace of Christ, bestowed in the New Law, but foreshadowed in the Old. Hence Augustine says (Contra Adimant. Manich. discip. xvii) that "there is little difference between the Law and the Gospel---fear and love."

Reply to Objection 1: As the father of a family issues different commands to the children and to the adults, so also the one King, God, in His one kingdom, gave one law to men, while they were yet imperfect, and another more perfect law, when, by the preceding law, they had been led to a greater capacity for Divine things.

Reply to Objection 2: The salvation of man could not be achieved otherwise than through Christ, according to Acts 4:12: "There is no other name . . . given to men, whereby we must be saved." Consequently the law that brings all to salvation could not be given until after the coming of Christ. But before His coming it was necessary to give to the people, of whom Christ was to be born, a law containing certain rudiments of righteousness unto salvation, in order to prepare them to receive Him.

Reply to Objection 3: The natural law directs man by way of certain general precepts, common to both the perfect and the imperfect: wherefore it is one and the same for all. But the Divine law directs man also in certain particular matters, to which the perfect and imperfect do not stand in the same relation. Hence the necessity for the Divine law to be twofold, as already explained.

Articulus 5

Argumentum 1

Ad quintum sic proceditur. Videtur quod lex divina sit una tantum. Unius enim regis in uno regno est una lex.

Sed totum humanum genus comparatur ad deum sicut ad unum regem; secundum illud Psalmi XLVI, rex omnis terrae deus.

Ergo est una tantum lex divina.

Argumentum 2

Praeterea, omnis lex ordinatur ad finem quem legislator intendit in eis quibus legem fert. Sed unum et idem est quod deus intendit in omnibus hominibus; secundum illud I ad Tim. II, vult omnes homines salvos fieri, et ad agnitionem veritatis venire.

Ergo una tantum est lex divina.

Argumentum 3

Praeterea, lex divina propinquior esse videtur legi aeternae, quae est una, quam lex naturalis, quanto altior est revelatio gratiae quam cognitio naturae. Sed lex naturalis est una omnium hominum. Ergo multo magis lex divina.

Sed Contra

Sed contra est quod apostolus dicit, ad Heb. VII, translato sacerdotio, necesse est ut legis translatio fiat.

Sed sacerdotium est duplex, ut ibidem dicitur, scilicet sacerdotium leviticum, et sacerdotium christi. Ergo etiam duplex est lex divina, scilicet lex vetus, et lex nova.

Corpus

Respondeo dicendum quod, sicut in primo dictum est, distinctio est causa numeri. Dupliciter autem inveniuntur aliqua distingui. Uno modo, sicut ea quae sunt omnino specie diversa, ut equus et bos. Alio modo, sicut perfectum et imperfectum in eadem specie, sicut puer et vir. Et hoc modo lex divina distinguitur in legem veterem et legem novam.

Unde apostolus, ad Gal. III, comparat statum veteris legis statui puerili existenti sub paedagogo, statum autem novae legis comparat statui viri perfecti, qui iam non est sub paedagogo.

Attenditur autem perfectio et imperfectio utriusque legis secundum tria quae ad legem pertinent, ut supra dictum est.

Primo enim ad legem pertinet ut ordinetur ad bonum commune sicut ad finem, ut supra dictum est.

Quod quidem potest esse duplex. Scilicet bonum sensibile et terrenum, et ad tale bonum ordinabat directe lex vetus; unde statim, exodi III, in principio legis, invitatur populus ad regnum terrenum chananaeorum. Et iterum bonum intelligibile et caeleste, et ad hoc ordinat lex nova.

Unde statim christus ad regnum caelorum in suae praedicationis principio invitavit, dicens, poenitentiam agite, appropinquavit enim regnum caelorum, Matth. IV. Et ideo Augustinus dicit, in IV contra faustum, quod temporalium rerum promissiones testamento veteri continentur, et ideo vetus appellatur, sed aeternae vitae promissio ad novum pertinet testamentum.

Secundo ad legem pertinet dirigere humanos actus secundum ordinem iustitiae. In quo etiam superabundat lex nova legi veteri, interiores actus animi ordinando; secundum illud Matth. V, nisi abundaverit iustitia vestra plus quam Scribarum et Pharisaeorum, non intrabitis in regnum caelorum.

Et ideo dicitur quod lex vetus cohibet manum, lex nova animum.

Tertio ad legem pertinet inducere homines ad observantias mandatorum. Et hoc quidem lex vetus faciebat timore poenarum, lex autem nova facit hoc per amorem, qui in cordibus nostris infunditur per gratiam christi, quae in lege nova confertur, sed in lege veteri figurabatur.

Et ideo dicit Augustinus, contra adimantum Manichaei discipulum, quod brevis differentia est legis et evangelii, timor et amor.

Ad 1

Ad primum ergo dicendum quod, sicut paterfamilias in domo alia mandata proponit pueris et adultis, ita etiam unus rex deus, in uno suo regno, aliam legem dedit hominibus adhuc imperfectis existentibus; et aliam perfectiorem iam manuductis per priorem legem ad maiorem capacitatem divinorum.

Ad 2

Ad secundum dicendum quod salus hominum non poterat esse nisi per christum; secundum illud Act. IV, non est aliud nomen datum hominibus, in quo oporteat nos salvos fieri.

Et ideo lex perfecte ad salutem omnes inducens, dari non potuit nisi post christi adventum. Antea vero dari oportuit populo ex quo christus erat nasciturus, legem praeparatoriam ad christi susceptionem, in qua quaedam rudimenta salutaris iustitiae continerentur.

Ad 3

Ad tertium dicendum quod lex naturalis dirigit hominem secundum quaedam praecepta communia, in quibus conveniunt tam perfecti quam imperfecti, et ideo est una omnium. Sed lex divina dirigit hominem etiam in quibusdam particularibus, ad quae non similiter se habent perfecti et imperfecti.

Et ideo oportuit legem divinam esse duplicem, sicut iam dictum est.