I. The law given by Moses is usually distinguished into three species: moral (treating of morals or of perpetual duties towards God and our neighbor); ceremonial (of the ceremonies or rites about the sacred things to be observed under the Old Testament); and civil, constituting the civil government of the Israelite people. The first is the foundation upon which rests the obligation of the others and these are its appendices and determinations. Ceremonial has respect to the first table determining its circumstances, especially as to external worship. Civil has respect to the second table in judicial things, although it lays down punishments for crimes committed against the first table.
II. The truth of this distinction appears from the diversity of the names by which it is designated in the Scriptures. The moral law is for the most part expressed by mtsvth (“precepts”), the ceremonial by chqym (“statutes”) and the judicial by mshptym (“judgments”), which the Septuagint renders by entolas, dikaiōmata and krimata. “I will speak unto thee all the commandments, and the statutes, and the judgments, which thou shalt teach them” (Dt. 5:31); so also in 6:1, 20; 7:11; and Lev. 26:46. Sometimes however these words are synonymous and used promiscuously (Ezk. 5:6; 20:11, 16, 18). But the distinction appears principally from the nature of the thing and the office of the law (whose it is to settle the order according to which man is joined to God and his neighbor). Now man is joined to God first by a certain internal and external likeness—in love and justice, holiness and truth, whose rule the moral law delivers. Again by the external signification and testification of those acts of divine worship (marks and symbols being employed) whose use the ceremonial law prescribes. Finally, what duty man owes to man, the civil law (applied more distinctly to the Israelites) explains. The moral law regards the Israelite people as men; the ceremonial as the church of the Old Testament expecting the promised Messiah; the civil regards them as a peculiar people who in the land of Canaan ought to have a republic suiting their genius and disposition.
III. Hence arises a manifold difference between the moral law and others both in origin (because the moral is founded upon natural right and on this account is known by nature; but the others upon positive right and on this account are from free revelation) and in duration. The former is immutable and eternal; the latter mutable and temporary. In regard to object, the one is universal embracing all; the others particular applying only to the Jews (the civil, indeed, inasmuch as it regarded them as a distinct state dedicated to God; the ceremonial, however, referring to their ecclesiastical state and state of minority and infancy). In regard to use, the moral is the end of the others, while the others are subservient to the moral. Thus far we have spoken of the moral; now we must discuss the ceremonial.
IV. The ceremonial law is the system of God’s positive precepts concerning the external worship in sacred things, prescribed to the ancient church, either for the sake of order or of signification. It is so called from the object about which it is conversant (viz., the sacred ceremonies or rites that were formerly to be observed in the external worship of God). This is so whether the word ceremony is derived from the Etruscan cerus, meaning “holy,” as sanctimonia from sanctus (according to Joseph Scaliger and Dionysius Gothofredus in notis ad Festum+); or from Ceres which (because the Gauls occupied Rome, they preserved the eternal fire and the vestal virgins) was called the sanctuary of the Roman people and the receptacle of the Roman sacred vessels. The Romans, for the sake of renumeration, called their sacred rites caeremoniae from Ceres (according to Valerius Maximus, Factorum et Dictorum Memorabilium 1.1.10 [ed. C. Kemp, 1966], p. 6; cf. Florus, lib. 1, cap. 13+). Or (what is more probable) from the Hebrew chrm which signifies a thing sacred and devoted to God.
V. It is marked by various names—now by chqym (as mshptym marks the judicial and mtsvth the moral); then by “the law of commandments in ordinances” (nomon tōn entolōn en dogmasi, Eph. 2:15) because its precepts are ordained (dedogmena) (sanctioned by the will of God) having no goodness except from the divine appointment; then by “carnal commandment” (entolēn sarkikēn, Heb. 7:16) and “carnal ordinances” (dikaiōmata sarkos, Heb. 9:10) because they are occupied with prescribing external and corruptible things (which are called carnal in the Scriptures); then by “weak and beggarly elements” (stoicheia asthenē kai ptōcha tou kosmou, Gal. 4:9) because they were the first rudiments and, as it were, the alphabet of the Jewish church. During her infantile state, she ought to have been instructed in them and able to do nothing by herself either for justification or for salvation.
—Francis Turretin, Institutes of Elenctic Theology, trans. George Musgrave Giger, vol. 2 (Phillipsburg, NJ: P&R Publishing, 1992–97), 11.24.1–5; pp. 145–147.