What is the moral law?
The moral law is the declaration of the will of God to mankind, directing and binding everyone to personal, perfect, and perpetual conformity and obedience thereunto, in the frame and disposition of the whole man, soul and body,1 and in performance of all those duties of holiness and righteousness which he oweth to God and man:2 promising life upon the fulfilling, and threatening death upon the breach of it.3
Scripture proofs
The Westminster Assembly's proof texts (KJV). The bracketed numbers in the answer above mark the clause each set of references supports; expand a row to read the verses.
1 Deut. 5:1–3, 31, 33; Luke 10:26–27; Gal. 3:10; 1 Thess. 5:23
Deut. 5:1 And Moses called all Israel, and said unto them, Hear, O Israel, the statutes and judgments which I speak in your ears this day, that ye may learn them, and keep, and do them.
Deut. 5:2 The LORD our God made a covenant with us in Horeb.
Deut. 5:3 The LORD made not this covenant with our fathers, but with us, even us, who are all of us here alive this day.
Deut. 5:31 But as for thee, stand thou here by me, and I will speak unto thee all the commandments, and the statutes, and the judgments, which thou shalt teach them, that they may do them in the land which I give them to possess it.
Deut. 5:33 Ye shall walk in all the ways which the LORD your God hath commanded you, that ye may live, and that it may be well with you, and that ye may prolong your days in the land which ye shall possess.
Luke 10:26 He said unto him, What is written in the law? how readest thou?
Luke 10:27 And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself.
For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.
And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
2 Luke 1:75; Acts 14:16
In holiness and righteousness before him, all the days of our life.
Who in times past suffered all nations to walk in their own ways.
3 Rom. 10:5; Gal. 3:10, 12
For Moses describeth the righteousness which is of the law, That the man which doeth those things shall live by them.
Gal. 3:10 For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.
Gal. 3:12 And the law is not of faith: but, The man that doeth them shall live in them.
This doctrine across the Standards
Where the Confession and the Westminster Shorter Catechism treat the same matter, so the question can be studied alongside its parallel statements.
In the Westminster Confession
XIX.1 God gave to Adam a law, as a covenant of works, by which he bound him and all …
God gave to Adam a law, as a covenant of works, by which he bound him and all his posterity to personal, entire, exact, and perpetual obedience; promised life upon the fulfilling, and threatened death upon the breach of it; and endued him with power and ability to keep it.
→ XIX.1 · Of the Law of GodXIX.2 This law, after his fall, continued to be a perfect rule of righteousness; and, as such, was delivered …
This law, after his fall, continued to be a perfect rule of righteousness; and, as such, was delivered by God upon mount Sinai in ten commandments, and written in two tables; the first four commandments containing our duty towards God, and the other six our duty to man.
→ XIX.2 · Of the Law of GodXIX.3 Beside this law, commonly called moral, God was pleased to give to the people of Israel, as a …
Beside this law, commonly called moral, God was pleased to give to the people of Israel, as a Church under age, ceremonial laws, containing several typical ordinances, partly of worship, prefiguring Christ, his graces, actions, sufferings, and benefits; and partly holding forth divers instructions of moral duties. All which ceremonial laws are now abrogated under the New Testament.
→ XIX.3 · Of the Law of GodXIX.4 To them also, as a body politic, he gave sundry judicial laws, which expired together with the State …
To them also, as a body politic, he gave sundry judicial laws, which expired together with the State of that people, not obliging any other, now, further than the general equity thereof may require.
→ XIX.4 · Of the Law of GodXIX.5 The moral law doth forever bind all, as well justified persons as others, to the obedience thereof; and …
The moral law doth forever bind all, as well justified persons as others, to the obedience thereof; and that not only in regard of the matter contained in it, but also in respect of the authority of God the Creator who gave it. Neither doth Christ in the gospel any way dissolve, but much strengthen, this obligation.
→ XIX.5 · Of the Law of GodXIX.6 Although true believers be not under the law as a covenant of works, to be thereby justified or …
Although true believers be not under the law as a covenant of works, to be thereby justified or condemned; yet is it of great use to them, as well as to others; in that, as a rule of life, informing them of the will of God and their duty, it directs and binds them to walk accordingly; discovering also the sinful pollutions of their nature, hearts, and lives; so as, examining themselves thereby, they may come to further conviction of, humiliation for, and hatred against sin; together with a clearer sight of the need they have of Christ, and the perfection of his obedience. It is likewise of use to the regenerate, to restrain their corruptions, in that it forbids sin; and the threatenings of it serve to show what even their sins deserve, and what afflictions in this life they may expect for them, although freed from the curse thereof threatened in the law. The promises of it, in like manner, show them God's approbation of obedience, and what blessings they may expect upon the performance thereof; although not as due to them by the law as a covenant of works: so as a man's doing good, and refraining from evil, because the law encourageth to the one, and deterreth from the other, is no evidence of his being under the law, and not under grace.
→ XIX.6 · Of the Law of GodXIX.7 Neither are the forementioned uses of the law contrary to the grace of the gospel, but do sweetly …
Neither are the forementioned uses of the law contrary to the grace of the gospel, but do sweetly comply with it: the Spirit of Christ subduing and enabling the will of man to do that freely and cheerfully which the will of God, revealed in the law, requireth to be done.
→ XIX.7 · Of the Law of GodIn the Westminster Shorter Catechism
Q.39 What is the duty which God requireth of man?
The duty which God requireth of man, is obedience to his revealed will.
→ Open Q.39Q.40 What did God at first reveal to man for the rule of his obedience?
The rule which God at first revealed to man for his obedience, was the moral law.
→ Open Q.40Q.41 Wherein is the moral law summarily comprehended?
The moral law is summarily comprehended in the ten commandments.
→ Open Q.41Q.42 What is the sum of the ten commandments?
The sum of the ten commandments is, To love the Lord our God with all our heart, with all our soul, with all our strength, and with all our mind; and our neighbour as ourselves.
→ Open Q.42Q.43 What is the preface to the ten commandments?
The preface to the ten commandments is in these words, I am the Lord thy God, which have brought thee out of the land of Egypt, out of the house of bondage.
→ Open Q.43Q.44 What doth the preface to the ten commandments teach us?
The preface to the ten commandments teacheth us, That because God is the Lord, and our God, and Redeemer, therefore we are bound to keep all his commandments.
→ Open Q.44Q.45 Which is the first commandment?
The first commandment is, Thou shalt have no other gods before me.
→ Open Q.45Q.46 What is required in the first commandment?
The first commandment requireth us to know and acknowledge God to be the only true God, and our God; and to worship and glorify him accordingly.
→ Open Q.46Q.47 What is forbidden in the first commandment?
The first commandment forbiddeth the denying, or not worshipping and glorifying the true God as God, and our God; and the giving of that worship and glory to any other, which is due to him alone.
→ Open Q.47Q.48 What are we specially taught by these words, 'before me', in the first commandment?
These words, before me, in the first commandment teach us, that God, who seeth all things, taketh notice of, and is much displeased with, the sin of having any other God.
→ Open Q.48Q.49 Which is the second commandment?
The second commandment is, Thou shalt not make unto thee any graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth: thou shalt not bow down thy self to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; and showing mercy unto thousands of them that love me, and keep my commandments.
→ Open Q.49Q.50 What is required in the second commandment?
The second commandment requireth the receiving, observing, and keeping pure and entire, all such religious worship and ordinances as God hath appointed in his Word.
→ Open Q.50+34 more — see the full topical treatment below.