The Westminster Shorter Catechism
Q. 40. What did God at first reveal to man for the rule of his obedience?
A. The rule which God at first revealed to man for his obedience, was the moral law.
The Westminster Shorter Catechism in Modern English:
Q.40. What rules did God first reveal for man to obey?
A. The rules He first revealed were the moral law.
1. How many laws has God given to man?
God gave to his people the moral law, which is still in force today, and ceremonial and judicial laws. These last two, as given to the Jews, have ceased to have any binding force under the Christian economy.
2. Is the moral law a rule of obedience to both believer and non-believer?
Yes, the moral law is a rule of obedience to both. The Westminster Confession teaches, "The moral law doth for ever bind all, as well justified persons as others, to the obedience thereof." (Chap. 21, Sec. V)
3. Can a man be saved by keeping the moral law?
No, a man is only saved by grace through faith. In addition, it would be impossible for man to keep the moral law perfectly.
4. If man cannot be saved by it, and yet is still bound by it, of what use is it?
The use of the moral law is that it is a "schoolmaster to bring us to Christ, that we might be justified by faith." (Gal. 3:24). The word "schoolmaster" is the idea of training and discipline in the passage cited. A pertinent passage here is 1 Timothy 1:8.
5. How does the law bring men to Christ?
The law brings men to Christ by convincing men of sin and by convincing them of its consequences if it is not atoned for and forgiven. It also awakens them to their need of a Saviour for that sin.
6. After a man is saved is the law of any further use?
The law is a perpetual reminder of the will of God for His creatures. For the believer it is intended as a rule of life and conduct which is absolute and unchanging. See Romans 7:6,12; Titus 2:11,12.