Chapter I: The Nomenclature of “Law,” § 2.
CHAPTER I: THE NOMENCLATURE OF “LAW”
The etymology of the noun lex.
§ 2. Cicero discusses the etymology of the word lex [“law”] in De legibus (bk. 1, not far from the beginning): “Scholars believe that ‘law’ comes from the Greek word for rendering to each one his due (ἀπò τoῦ νἑμɛıν). I, for one, think that it comes from our word legendo [‘choosing’]. For as they place the power of equity in law, we give it the power of selection. Yet both of these are characteristic of law.” According to Varro, the word lex is derived either from legendo [“reading”], because laws generally were read publicly, or from ligando [“binding”], because the law binds to obedience all those to whom it applies.
** (Lex is derived from ligando, first, because laws oblige people to do some things and to avoid others; second, because magistrates bind their subjects to themselves with laws; third, because all societies are bound by certain laws. Thus in Hosea 11:4 and Ps. 2:3 some take “cords” and “bands” to mean the Law. However, if lex were indeed derived from ligando, it would be called lix rather than lex.) **
[Or perhaps it is] from deligendo [“choosing”] because, according to Cicero, it points out the choice between what we should do and not do, what we should seek or flee. The Hebrew 
(Torah) comes from 
, which primarily means “to teach.” From this we conclude that the word “law” is used in general for “teaching” with regard to its etymology. The second meaning of 
is “to aim at,” which implies that we ought to consider the Law as the target at which we aim in all our doings, unless we wish to “shoot our arrows without aiming,” which is ἁμαρτἁνɛıν [“to miss the mark, to sin”]. Finally, it means “to enrich people’s minds with instruction,” just as rains enrich the earth. This proves the value and usefulness of this doctrine.
** Some derive it from 
(“he feared”) because the Law strikes people with fear. Some take it from 
, which means “he investigated, he searched out,” because, like a mirror, it sets before our eyes the uncleanness of our very nature. The Greek νόμoς [“law”] comes from νόoς [“mind”] according to Plato (De legibus, bk. 12), both because it illumines the mind and because the law of nature flows from the precept of the mind; or it comes from νέμɛıν [“to distribute”] both because it commands that each one grant everyone his due and because it distributes to each person his duties and obligations. **
Homonyms.
§3. Since words of like meaning confuse the genuine knowledge of matters unless they are distinguished, and especially since the equivocation of this word long ago produced infamous errors (as Chemnitz teaches, Loci, part 2, p. 4),1 therefore we must note carefully the various different meanings the word “law” has in Scripture. The proper and most frequent meaning of “law” is that it denotes the doctrine of works: the rule of what should be done and what should be avoided. We use “law” in this sense in this commonplace. In this way, the word “law” is used either generally for all law or in particular for the moral Law (Exod. 24:12: “And I shall give you the tables of stone and the Law”) or for the ceremonial law (Luke 2:23: “As it is written in the law of the Lord”) or for the judicial law (John 19:7: “We have a law, and according to that law He ought to die”).
In general “law” signifies the totality of divinely revealed doctrine. Ps. 1:[1–]2: “Blessed is the man who meditates on the Law of the Lord day and night.” In this sense it is applied specifically to the doctrine of the Gospel, even though the Gospel is diametrically opposed to the Law properly speaking. However, whether this word is used generally or specifically must be determined from the context of any given passage. Whenever that which is characteristic of the Gospel is attributed to “law,” it is obvious that the word “law” does not mean the Law properly speaking—that is, the doctrine of works—but generally, the totality of divinely revealed doctrine or even the doctrine of the Gospel in particular. Thus Isa. 2:3: “Out of Zion will go forth law,” which is clearly not the Law, properly speaking. Instead, this means the solemn proclamation of the Gospel, for the Law was published on Mount Sinai, not Mount Zion. Ps. 19:7–8: “The law of the Lord is perfect, reviving the soul. The precepts of the Lord are right, rejoicing the heart.” Here the law is said to revive, rejoice, and lift the heart. Yet the Law, properly speaking, works wrath (Rom. 4:15). Thus the apostle speaks of “the law of faith” (Rom. 3:27), even though the righteousness which is of the Law and the righteousness of faith are opposed to each other (Rom. 10:5–6). Therefore the general word “law” there means “teaching.”
Materially the noun “law” is used for the sacred books in which the doctrine of the Law has been written down. Even in this sense the word is used in different ways. At times it means generally all the books of the Old Testament. Thus in John 10:34 even the Psalms are included under the word “law”: “Is it not written in your Law: ‘I said, you are gods’?” John 15:25: “It is written in the Law: ‘They hated Me without a cause.’” In 1 Cor. 14:21 Paul cites a statement from Isaiah which is said to have been written “in the Law.” At times it means the Pentateuch of Moses specifically, namely, whenever the scripture of the Law is distinguished from the Prophets and Psalms. Luke 24:44: “Everything written about Me in the Law of Moses and the Prophets and the Psalms must be fulfilled.” Rom. 3:21: “The Law and the Prophets bear witness to the righteousness of God.” In this sense the rabbinic scholars call the books of Moses the 
(Torah) At times the word “law” denotes most specifically the scripture of the Decalogue, as Luke 10:26: “What is the first commandment in the Law?” Augustine (treatise 48 on John): “The Lord called all the Scriptures ‘Law’ generally (John 10:34), though He elsewhere specifically says ‘Law’ and distinguishes it from the Prophets.” Retract. (bk. 1, ch. 5): “We also specifically say ‘Law,’ as in ‘the Law and the Prophets’; and generally, since the Prophets, too, are in the Law.” The noun “law” is not only used conjointly for all the books of Moses but also distinctly for individual books of Moses. For instance, it is used: (1) For the first book [Genesis]. Gal. 4:21–22: “Do you not read the Law? For it is written that Abraham had two sons.” That is from Gen. 16:15. (2) It is used for the second book [Exodus]. Matt. 12:5: “Or have you not read in the Law how on the Sabbath the priests in the temple violate the Sabbath?” which is from Exod. 29:33. (3) It used for the third book [Leviticus]. John 8:5: “Now in the Law, Moses commanded that we stone such,” which is from Lev. 20:10. (4) It is used for the fourth book [Numbers]. Heb. 7:5: “They take tithes according to the Law,” which comes from Num. 18:21. (5) It is used for the fifth book [Deuteronomy]. John 7:51: “Does our Law judge a man without first giving him a hearing?” which is from Deut. 17:8. In this last passage there is also a meaning that takes “Law” for the Old Testament and that denotes their entire political state and the establishment of the priesthood that God had prescribed for the people of Israel through Moses. This meaning occurs frequently in the Epistle to the Hebrews as often as “Law” is opposed to the New Testament. Matt. 11:13: “For the Law and the Prophets prophesied until John.”
Synecdochically the word “law” is used for the harshness and the curse of the Law. This happens when it is opposed to grace. Rom. 6:14: “You are not under law but under grace.” Gal. 5:18: “If you are led by the Spirit, you are not under the law.” Here it is clear that Paul does not mean obedience, but the harshness of the curse by which the Law accuses and condemns all in whom any sin adheres without any leniency [ἐπıɛíκɛıα], and does not approve of or accept any obedience unless it be complete in every instance and pure in every respect.
By metonymy it is used for a moving and impelling power, force, or efficacy, as “the law of sin” (Rom. 7:25), “the law of death” (Rom. 7:6), “the law in my members” (Rom. 7:23), “the law of the Spirit of life” (Rom. 8:2). Augustine (83 QQ, q. 66) believes that it is called “‘the law of sin’ because it is imposed on sinners. It is called ‘the law of death’ because the wages of sin is death, the sting of death is sin, and the power of sin is the law.’ ” Those are the more important meanings of this word.
Less important and secondarily the word is used: (1) For the custom and law of the Gentiles. Dan. 6:15: “The law of the Medes.” Acts 18:13: “This man is persuading people to worship God contrary to the law.” (2) It is used for upright instruction. Prov. 1:8: “Reject not your mother’s law.” (3) It is employed for the subjection and obedience that a person is bound to show to others by divine and human right. Rom. 7:3: “A woman is freed from the law of her husband.” 1 Cor. 7:39: “She is bound to the law.”
Synonyms.
§4. In Psalms 119 and 19 the Holy Spirit sets forth a very beautiful series of synonyms attributed to the Law. Chemnitz (Loci, part 2, p. 8) gives us a careful explanation of them.2 The following are the more important appellations: 
(eduth, μαρτύριoν “testimony”), because the Law provides testimony about the will of God and convicts us of sin. When Moses repeats the Law in Deut. 4:26, he uses the root 
(heid): “I call heaven and earth to witness against you this day.” It is called 
(derekh, ἡ ὁδός, “the way”), because the Law shows us the way of good works in which we should walk; 
(pekude in the construct state, ἐντoλαί, “commands”) from 
(pakad), which means “to entrust, to delegate, to visit, to require,” for God has entrusted His Law to man as a sort of deposit and visits transgression of it with just punishments.
** In Gen. 26:5 the commandments of God are called 
(God’s “guard”), because people ought to observe and guard them: “Abraham kept My guard (
), My commandments (
), My statutes (
), and My laws (
).” **
It is called 
(khuqqim, δικαιώματα), which frequently means legal rituals and ceremonies, as does also the word 
(mishpatim, τὰκρίματα, “judgments, forensic or judicial laws”). Yet both these words, especially when placed apart, are general, because the law is God’s statute, and its judgment is against sin. It is called 
(mitsvah, ἐντoλή, “commandment”), because it binds to observance, and it comes from 
(tsivah), which means “to order, to commit a responsibility to, to decree, to make answerable for,” etc. It is called 
(imre in the construct state, τὰ λόγιά, oἱ λόγoι, “the utterances of God”), because the Law was solemnly promulgated by God’s own voice. It is called 
(tsedek, ἡ δικαιoσύνη, τò δικαίωμα, “righteousness, justice”), because the Law prescribes the norm of justice. Another word is 
(berith, ἡ διαθήκη, “treaty, covenant”), because in the Law God enters upon a covenant with His people. It is called 
(yirath Jehovah, ὁ φόβoς κυρίoυ, “the fear of the Lord”) by metonymy, because the sum of the Law consists of the fear and love of God. It is also called 
(asereth haddebarim, “the ten words”), because the sum of the moral Law consists of the Decalogue. The expression “moral Law” is indeed a very common one; yet it must be explained accurately. The divine Law, you see, requires an integrity not only of conduct [morum] and of external actions but also of inner desires and, in fact, of one’s entire nature. In regard to names for the Law, see Justin [Martyr], Quaest. et resp. ad orthod., q. 92.
Different names for the Law.
§5. On this point Luther observes (Galatians, ch. 5, [Jena] Latin edition, vol. 4, p. 149) that the apostle Paul attributes various names to the Law.3 When the Law is considered in itself as a teaching which God has given, he adorns it with honorable titles:
“The Law is holy, and the commandment is holy, just, and good” (Rom. 7:12); “the very commandment which was to life” (Rom. 7:10); “the Law is good” (1 Tim. 1:8); “living oracles” (Acts 7:38). On the other hand, when the Law is considered in the article of justification and in comparison with the doctrine of the Gospel and also with respect to our corrupt nature, the apostle then speaks of the Law almost with an ignominious contempt. He calls it a “custodian” and “confining prison” (Gal. 3:23–24, “which no one loves,” says Luther4 ); “a yoke of slavery” (Gal. 5:1); “the power of sin” (1 Cor. 15:56); “the bringer of wrath and death” (Rom. 4:15; 7:5); “the weak and worthless elementary principles of the world” (Gal. 4:[9]); “a ministry of death and condemnation” and “a killing letter” (2 Cor. 3:6, 7, 9); “the handwriting that was against us” (Col. 2:14); “a covenant bearing children for slavery” (Gal. 4:24). In the following statements the blessed apostle reconciles these diverse attributes: Rom. 7:10–11: “The very commandment” (given by God) “which was to life proved to be death for me. For sin, finding opportunity in the commandment, deceived me” (because by nature I have been sold under sin, which the word of God’s Law reveals and indicts); 1 Tim. 1:8: “The Law is good if one uses it lawfully.”
1 Chemnitz’s Works 8:591–96.
2 Cf. Chemnitz’s Works 8:594–96.
3 Lectures on Galatians (1531/1535), AE 27:3–105 (WA 40/2:1–134).
4 Cf. Lectures on Galatians (1531/1535), AE 26:336 (WA 40/1:519).