Since sin is "lawlessness" (ἀνομία), it is necessary to know what law Scripture means when it describes sin as a "transgression of the Law." If the doctrine of the divine Law is perverted by man's adding to or subtracting from it, then also the doctrine of sin must needs be perverted. It is therefore necessary that we define that Law the transgression of which makes a thought or deed sinful. The Formula of Concord describes the Law in the sense in which it is here used as a "divine doctrine in which the righteous, immutable will of God is revealed, what is to be the quality of man in his nature, thoughts, words, and works in order that he may be pleasing and acceptable to God." Thor. Decl., Art. V, 17. This definition is Scriptural; for only God can decree laws for men, since this is His divine prerogative, Jas. 4, 12. Laws enacted by men are binding only if God Himself has given men authority to make them and so has given the human laws divine sanction. This is the case with all laws of civil government and with all parental commandments, Rom. 13, 1; Col. 3, 20, provided they do not contradict the divine Law, Acts 5, 29. But this is not the case with the so-called "laws of the Church," since God has expressly withheld from the Church legislative authority, Matt. 23, 10. Hence in the Church only those laws are to be acknowledged as binding which have been enacted by God Himself.
In all matters where no special divine laws obtain, decisions should be reached by Christians through mutual agreement on the basis of Christian love, 1 Cor. 16, 14. Of the Pope, Luther rightly says that he has filled the whole world with a satanic obedience, since he has taught men to obey, not the Law of God, but his own pernicious laws (St. L., I, 765). While it is true that only God's immutable will constitutes the divine Law which binds all men, it is equally true that the whole divine Law, with all its demands and prohibitions, must be taught by the Church. For as little as the Church has authority to make laws of its own, just so little has it authority to discard any laws which God has made, Matt. 5, 17-19; Mark 7, 6-13.
Since the Old Testament ceremonial laws have been abolished through the coming of Christ, Gal. 4, 9-11; 5, 1-4, they are no longer in force in the New Testament, Col. 2, 16, so that the immutable will of God which now obligates all men must be identified with the Moral Law, Matt. 22, 37-40; 1 Tim. 1, 5. For this reason we define sin in general as a deviation from the divine Moral Law, no matter whether that Law has been written in the human heart or communicated to man by positive precept. For the Jews in the Old Testament also every deviation from the ceremonial or political laws constituted a sin; but since in the New Testament these laws have been abolished by God's express will, Col. 2, 16, it would be a sin to reinstitute them as necessary and binding upon the consciences of New Testament believers, Matt, 15, 9; Gal. 5, 1--4. The laws which God enacted as temporary man must not declare to be permanent.