Quote heavily modified for clarity and modernization.
Let us then first examine the reason for the ordering of Dionysius, in which we see, that, as said above (A), 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."
As regards the end, three things may be considered. For firstly we consider the end; then we acquire perfect knowledge of the end; thirdly, we fix our intention on the end; of which the second is an addition to the first, and the third an addition to both. And because God is the end of creatures, as the leader is the end of an army, as the Philosopher says (Metaph. xii, Did. xi, 10); so a somewhat similar order may be seen in human affairs. For there are some who enjoy the dignity of being able with familiarity to approach the king or leader; others in addition are privileged to know his secrets; and others above these ever abide with him, in a close union. According to this similitude, we can understand the disposition in the orders of the first hierarchy; for the "Thrones" are raised up so as to be the familiar recipients of God in themselves, in the sense of knowing immediately the types of things in Himself; and this is proper to the whole of the first hierarchy. The "Cherubim" know the Divine secrets supereminently; and the "Seraphim" excel in what is the supreme excellence of all, in being united to God Himself; and all this in such a manner that the whole of this hierarchy can be called the "Thrones"; as, from what is common to all the heavenly spirits together, they are all called "Angels."