refraining from these opposites is a necessary consequence of doing what is commanded, not an intended object of the command. Thus, if someone omits what is commanded, he is punished for that omission, not for the opposite acts with which he occupied himself. Likewise, the intent of the one who prohibits something is that it not occur, not that any of its opposites be done. If someone refrains from it while engaging in an opposite act, this is a necessary consequence of refraining.

Accordingly, if someone refrains from one forbidden act by committing another, he is punished for the latter. It is not said that he has fulfilled an obligation by refraining from the former, because what is intended is that the former not occur. Thus, the permissible act with which he occupies himself instead of a forbidden act is not the object of a deliberate command, either to perform it or to undertake it in obedience. Rather, he has been forbidden to commit the unlawful act, and refraining from what is forbidden necessarily involves engaging in one of its opposites. This therefore occurs as a necessary consequence of refraining from what is forbidden; it is not an obligation as defined in our statements:

“An obligation is that for whose omission a person is blamed and punished,”

or:

“That whose omission is a cause for blame and punishment.”

Thus, our statements:

“Whatever is indispensable to fulfilling an obligation is itself obligatory,”

or:

“One must use what is not itself obligatory as a means to fulfill an obligation,”

entail requiring the necessary means. There remains an established distinction between the “first” and the “second” kind of obligation. Whoever omits the first is blamed and punished. The second, however, is obligatory in the sense that it must occur—that is, the obligation cannot be fulfilled without it. It is commanded as a means, and a person is rewarded for it, but punishment is not for omitting it.