Per actionem ad beatitudinem pervenitur quia operatio hominis non praeexigitur ad consecutionem beatitudinis propter insufficientiam divinae virtutis beatificantis, sed ut servetur ordo in rebus.
Happiness is obtained through works because works are necessary to man in order to gain Happiness, not on account of the insufficiency of the Divine power which bestows Happiness, but that the order in things be observed.
Ut enim dicitur in II de caelo, "eorum quae nata sunt habere bonum perfectum, aliquid habet ipsum sine motu, aliquid uno motu, aliquid pluribus". Habere autem perfectum bonum sine motu, convenit ei quod naturaliter habet illud. Habere autem beatitudinem naturaliter est solius Dei. Unde solius Dei proprium est quod ad beatitudinem non moveatur per aliquam operationem praecedentem.
For as is stated in De Coel. ii, 12, "of those things that have a natural capacity for the perfect good, one has it without movement, some by one movement, some by several." Now to possess the perfect good without movement, belongs to that which has it naturally: and to have Happiness naturally belongs to God alone. Therefore it belongs to God alone not to be moved towards Happiness by any previous operation.
Cum autem beatitudo excedat omnem naturam creatam, nulla pura creatura convenienter beatitudinem consequitur absque motu operationis, per quam tendit in ipsam. Sed Angelus, qui est superior ordine naturae quam homo, consecutus est eam, ex ordine divinae sapientiae, uno motu operationis meritoriae, ut in primo expositum est. Homines autem consequuntur ipsam multis motibus operationum, qui merita dicuntur. Unde etiam, secundum philosophum, beatitudo est praemium virtuosarum operationum.
Now since Happiness surpasses every created nature, no pure creature can becomingly gain Happiness, without the movement of operation, whereby it tends thereto. But the angel, who is above man in the natural order, obtained it, according to the order of Divine wisdom, by one movement of a meritorious work, as was explained in Ia q62 a5; whereas man obtains it by many movements of works which are called merits. Wherefore also according to the Philosopher (Ethic. i, 9), happiness is the reward of works of virtue.
Apostolus dicit, Rom. IV, beatitudinem hominis esse cui Deus confert iustitiam sine operibus.
The Apostle says (Romans 4:6) that Happiness is of the man "to whom God reputeth justice without works."
Apostolus loquitur de beatitudine spei, quae habetur per gratiam iustificantem, quae quidem non datur propter opera praecedentia. Non enim habet rationem termini motus, ut beatitudo, sed magis est principium motus quo ad beatitudinem tenditur.
The Apostle is speaking of the Happiness of Hope, which is bestowed on us by sanctifying grace, which is not given on account of previous works. For grace does not have the formal aspect of a term of movement, as Happiness does; rather, it is the principle of the movement that tends towards Happiness.