Article — Merkelbach, Summa Theologiae Moralis
Article V: On Cessation of the End
398. The intrinsic end of law is that good which the law immediately regards and intends, or the proximate formal motive on account of which it was enacted. It ceases when it has already been obtained or can no longer be obtained, for example, the health of the pontiff to be obtained, if it has been obtained or if the pontiff dies. But it can cease either negatively or contradictorily, when observance of the law is no longer useful for the end: this is simple cessation; or positively and contrarily, when from being just, useful, and morally possible it has become, on account of circumstances, unjust, harmful, or very difficult: this is called change of matter.
399. The rules concerning cessation of the end are usually stated as follows:
I. When the total or adequate end of the law ceases (even negatively) in the universal, that is, with respect to the whole community or the greater part, and indeed permanently, the law ceases, because it becomes useless to the community, at least with respect to that which it intended, nor does the legislator will to obligate when the end intended by him is lacking; a fortiori if it ceases positively and the law becomes universally harmful. Hence the axiom: when the reason of the law ceases, its disposition ceases.
II. When a partial end ceases, the law does not cease, provided the end of the law is sufficient; for example, prayer for peace and fair weather does not cease when this has been obtained.
III. When the end ceases in the particular (with respect to one person or for a time), the law in no way ceases, because it intends the general good; but if it becomes harmful or too burdensome, the law itself does not cease, but as regards the particular case it can fail to obligate by epikeia, if it becomes too grave.
400. Corollary. - Hence for the cessation of law from within, three conditions are required. Namely, the final cause must cease totally as to all parts of the law, universally for the whole community, and constantly; otherwise the law is only suspended.