III–IV. Perfection must be proportioned to the subject; mortal and eternal goods
III. But this perfection of the thing that is perfected is necessarily proportioned, so that it cannot be lesser or worse than the thing to be perfected.
For it would not be perfection if it could not perfect its subject — or, what amounts to the same, actuate and exhaust that potency which it has toward perfection, and sufficiently fill its appetite.
IV. Hence it is that to mortal and fleeting things mortal and fleeting perfections also belong, which affect and perfect them as long as they last; but if any thing is eternal and immortal, its good too is eternal and immortal.
For it would be absurd if the perfection of an eternal and immortal thing were placed in something that is by its nature fragile, flowing, and liable to ruin, among those things that are below the first heaven.
Latin
III. Haec autem perfectio rei, quae perficitur, necessario proportionata est, ita, ut re perficienda minor aut deterior esse non possit. Neque enim perfectio foret, si subjectum suum perficere seu, quod idem pollet, potentiam illam, quam habet ad perfectionem, actuare & exhaurire, appetitumque ejus sufficienter explere non posset. IV. Hinc est, quod rebus mortalibus & caducis mortales quoque & caducae conveniunt perfectiones, quae eas, quamdiu durant, afficiunt ac perficiunt: si vero quaequam res aeterna est & immortalis, bonum quoque ejus aeternum est & immortale. Nam absurdum foret, si perfectio rei aeternae & immortalis collocaretur in quopiam, quod sit sua natura fragile, fluxum & interitui obnoxium, cum iis, quae sunt infra caelum primum.