(CG 3/76). That the Providence of God watches immediately over all Individua... (Book 3. God, the End of Creatures) (Summa Contra Gentiles) (Aquinas, Thomas, St.)

IT belongs to the dignity of a ruler to have many ministers and diversity of servants to carry his command into execution, the height and greatness of his lordship appearing by the multitude of persons of various ranks who are subject to him: but no dignity of any ruler is comparable with the dignity of the divine government: it is suitable therefore that the arrangements of divine providence be carried into execution by divers grades of agents.

6. As the cause is superior to the effect, the order of causes is nobler than that of effects: in that order therefore the perfection of divine providence is better shown. But if there were not intermediate causes carrying divine providence into execution, there would be in creation no order of causes, but only of effects. The perfection therefore of divine providence requires that there should be intermediate causes carrying it into execution.

Hence it is said: Bless the Lord, all his powers, ye ministers that do his word (Ps. cii, 21): Fire, hail, snow, stormy winds that do his word (Ps. cxlviii, 8).