>>610829
Then we might use Aquinas
>nature of God's ministering spirits and divine attendants
There must be some incorporeal creatures. For what is principally intended by God in creatures is good, and this consists in assimilation to God Himself. And the perfect assimilation of an effect to a cause is accomplished when the effect imitates the cause according to that whereby the cause produces the effect; as heat makes heat. Now, God produces the creature by His intellect and will (I:14:8; I:19:4). Hence the perfection of the universe requires that there should be intellectual creatures. Now intelligence cannot be the action of a body, nor of any corporeal faculty; for every body is limited to "here" and "now." Hence the perfection of the universe requires the existence of an incorporeal creature.
The ancients, however, not properly realizing the force of intelligence, and failing to make a proper distinction between sense and intellect, thought that nothing existed in the world but what could be apprehended by sense and imagination. And because bodies alone fall under imagination, they supposed that no being existed except bodies, as the Philosopher observes (Phys. iv, text 52,57). Thence came the error of the Sadducees, who said there was no spirit (Acts 23:8).
But the very fact that intellect is above sense is a reasonable proof that there are some incorporeal things comprehensible by the intellect alone.
>function of God's ministering spirits and divine attendants
The grades of the angelic orders are assigned by Gregory (Hom. xxiv in Ev.) and Dionysius (Coel. Hier. vii), who agree as regards all except the "Principalities" and "Virtues." For Dionysius places the "Virtues" beneath the "Dominations," and above the "Powers"; the "Principalities" beneath the "Powers" and above the "Archangels." Gregory, however, places the "Principalities" between the "Dominations" and the "Powers"; and the "Virtues" between the "Powers" and the "Archangels." Each of these placings may claim authority from the words of the Apostle, who (Ephesians 1:20-21) enumerates the middle orders, beginning from the lowest saying that "God set Him," i.e. Christ, "on His right hand in the heavenly places above all Principality and Power, and Virtue, and Dominion." Here he places "Virtues" between "Powers" and "Dominations," according to the placing of Dionysius. Writing however to the Colossians (1:16), numbering the same orders from the highest, he says: "Whether Thrones, or Dominations, or Principalities, or Powers, all things were created by Him and in Him." Here he places the "Principalities" between "Dominations" and "Powers," as does also Gregory.
Let us then first examine the reason for the ordering of Dionysius, in which we see, that, as said above (Article 1), the highest hierarchy contemplates the ideas of things in God Himself; the second in the universal causes; and third in their application to particular effects. And because God is the end not only of the angelic ministrations, but also of the whole creation, it belongs to the first hierarchy to consider the end; to the middle one belongs the universal disposition of what is to be done; and to the last belongs the application of this disposition to the effect, which is the carrying out of the work; for it is clear that these three things exist in every kind of operation. So Dionysius, considering the properties of the orders as derived from their names, places in the first hierarchy those orders the names of which are taken from their relation to God, the "Seraphim," "Cherubim," and "Thrones"; and he places in the middle hierarchy those orders whose names denote a certain kind of common government or disposition—the "Dominations," "Virtues," and "Powers"; and he places in the third hierarchy the orders whose names denote the execution of the work, the "Principalities," "Angels," and "Archangels."