“Moral law is law which moral beings are at all times under obligation to obey. It is binding upon every moral creature under all circumstances. To a moral law there can be no exception. If there can be an exception to a moral law, but a general rule that is to be interpreted as the case demands. If man is to be a law to himself, moral law must proceed from the moral nature, and as thus proceeding it will have, according to what has be said two branches – the law of righteousness, and the law of obligation. The law of righteousness respects rights, and its precept is, No right may be violated. The law of obligation respects principles of action as higher and lower and good as varying in its quality, and as greater or less.
Its precept is, Choose for yourselves and for others the higher principle of action, and the nobler and greater good. These taken together are the moral law as derived from the moral nature. To this law there can be no exception, in this world or any other. Of this law the underlying idea is that of a good. Without that idea there can be no idea of rights, or of an obligation to do anything for ourselves or for others. As we shall see hereafter, this law in its two branches is coincident with the law of love. No one who loves another can violate his rights, or fail to do for him what obligation demands.
When moral law, in either form of it as presented above, is placed before an unperverted moral being capable of understanding it, obligation to obey it is intuitively and necessarily affirmed. If it were not, man would not have a moral nature. The obligation is at first recognized in a particular case, but immediately and necessarily, not by generalization or induction, assumes a general form. It is thus, by the resolution of the two branches of the law into the law of love, that the moral law is the law of obligation. Where there is obligation there is moral law, and where there is no obligation there is no moral law.
The affirmation of obligation implies both a command and a penalty, and thus becomes law. In this it differes from a rule. A rule tells us how to do a thing. A law tells us what to do and commands us to do it, but becomes law only as it is enforced by penalty, or by punishment. This affirmation of obligation carries with it the force of the word ‘ought’; but unless it is supposed to express the will of God with his authority lying back of it, it will be, as men now are, of small force in controlling the appetites and passions. Men fear but slightly the reaction upon themselves of violated law, which may be regarded as penalty in distinction from punishment.
The sphere of moral law is the control of the man himself in his preferences and choices. Disregarding outward manifestations it takes cognizance of that which can be known only to the individual himself and to God, of that which in the Scriptures is called “the heart.” That is its grand peculiarity. It asserts it prerogative just where moral forces have play and moral battles are wages.
This law, or affirmation of obligation, comes from within a man, as any law must by which a man is “a law unto himself.” It is given by the moral reason when the occasion comes, and is possible only on the condition that there be a being possessed of intellect, sensibility and will. With this condition the idea and affirmation of obligation is given by the moral reason, just as the idea of beauty is given by the aesthetic reason on condition of intellect and sensibility, or as the idea of space is given by the pure reason.
But though the law is thus from within the man, it is yet not of him as having choice and will, but comes by necessity, and as from a somewhat apart from himself. And hence the comparison by Kant of the moral law to the starry heavens as equally wonderful, and as equally apart from himself. Only too, in the fact of a moral law thus given, could Kant have found what he regarded as the strongest proof of the being of a God who is a moral governor. It is an adequate, and the only adequate proof. From the law of cause and effect, as well as from the revealed fact that we are in the image of God, we may infer that a moral nature and so moral law, are involved in the personality of God as they are in our own.”
Hopkins, Mark (1887). The Law Of Love and Love As a Law. New York; Charles Scribner’s Sons. pgs 80-84.