The duty which God requireth of man is obedience to his revealed will.
The rule of obedience revealed to Adam in the estate of innocence, and to all mankind in him, beside a special command not to eat of the fruit of the tree of the knowledge of good and evil, was the moral law.
The moral law is the declaration of the will of God to mankind, directing and binding every one to personal, perfect, and perpetual conformity and obedience thereunto, in the frame and disposition of the whole man, soul and body, and in performance of all those duties of holiness and righteousness which he oweth to God and man: promising life upon the fulfilling, and threatening death upon the breach of it.
Although no man, since the fall, can attain to righteousness and life by the moral law; yet there is great use thereof, as well common to all men, as peculiar either to the unregenerate, or the regenerate.
The moral law is of use to all men, to inform them of the holy nature and will of God, and of their duty, binding them to walk accordingly; to convince them of their disability to keep it, and of the sinful pollution of their nature, hearts, and lives; to humble them in the sense of their sin and misery, and thereby help them to a clearer sight of the need they have of Christ, and of
the perfection of his obedience.
The moral law is of use to unregenerate men, to awaken their consciences to flee from wrath to come, and to drive them to Christ; or, upon their continuance in the estate and way of sin, to leave them inexcusable, and under the curse thereof.
Although they that are regenerate, and believe in Christ, be delivered from the moral law as a covenant of works, so as thereby they are neither justified nor condemned: yet, beside the general uses thereof common to them with all men, it is of special use to show them how much they are bound to Christ for his fulfilling it, and enduring the curse thereof in their stead and for their good; and thereby to provoke them to more thankfulness, and to express the same in their greater care to conform themselves thereunto as the rule of their obedience.
The moral law is summarily comprehended in the ten commandments, which were delivered by the voice of God upon mount Sinai, and written by him in two tables of stone; and are recorded in the twentieth chapter of Exodus. The four first commandments containing our duty to God, and the other six our duty to man.
For the right understanding of the ten commandments, these rules are to be observed: