The sinner ought to will the good of being. This he knows, and if he be a moral agent, which is implied in his being a sinner, he cannot but assume this as a first truth, that he ought to will the good of being in general, and not his own gratification, as an end. This truth he always and necessarily takes with him, in the form of an assumption of a universal truth. He knows, and cannot but know, that he ought to will the good of God and of the universe, as an end, instead of willing his own good as an end. Now, this being necessarily assumed by him as a first truth, it is no more essential to sin, that he should think at the time that a particular intention is or would be sinful, than it is essential to murder, that the law of causality should be distinctly before the mind, as an object of attention, when the murderer aims the fatal weapon at his victim.
Murder consists in a selfish intention to kill a human being.
I point a pistol at my neighbour's head with an intention to gratify a spirit of revenge or of avarice, or some such desire, by taking his life. I no more think of that law of causality which alone will secure the effect at which I aim, than I do of my obligation, and of the moral character of my intention. Nevertheless, I assume, and cannot but assume, those first truths at the moment of my intention. The first truths of reason are those, as has been repeatedly said, that are necessarily known and assumed by all moral agents. In every endeavour to do anything, I assume the truth of causality, and generally without being conscious of any such assumption.