It remains to consider whether infinity belongs to Him in point of spiritual greatness. According then to the completeness of its actuality is the measure of the greatness of its power. But in God infinity can be understood negatively only, inasmuch as there is no term or limit to His perfection. And so infinity ought to be attributed to God. The conclusion is that He is infinite.
Actuality is more perfect, the less admixture it has of potentiality.
There cannot be conceived any mode in which any perfection can be had more perfectly than by him, who is perfect by his essence, and whose being is his own goodness. He is therefore infinite in goodness. But this direction of our intellect to the infinite would be in vain, if there were not something intelligible that is infinite. If then our understanding can conceive something greater than any finite being, the conclusion remains that God is not finite. Every agent shows greater power in action, the further from actuality is the potentiality which it reduces to actuality, as there is need of greater power to warm water than to warm air.