Reply Obj. 1: An operation can be intellectual in two ways. In one way, as dwelling in the intellect itself, as contemplation; such an operation does not demand to occupy a place; indeed, as Augustine says (De Trin. iv, 20): "Even we ourselves as mentally tasting something eternal, are not in this world." In another sense an action is said to be intellectual because it is regulated and commanded by some intellect; in that sense the intellectual operations evidently have sometimes a determinate place.
Reply Obj. 2: The empyrean heaven belongs to the angelic dignity by way of congruity; forasmuch as it is congruous that the higher body should be attributed to that nature which occupies a rank above bodies. Yet an angel does not derive his dignity from the empyrean heaven; so when he is not actually in the empyrean heaven, nothing of his dignity is lost, as neither does a king lessen his dignity when not actually sitting on his regal throne, which suits his dignity.
Reply Obj. 3: In ourselves the purity of contemplation is obscured by exterior occupation; because we give ourselves to action through the sensitive faculties, the action of which when intense impedes the action of the intellectual powers. An angel, on the contrary, regulates his exterior actions by intellectual operation alone. Hence it follows that his external occupations in no respect impede his contemplation; because given two actions, one of which is the rule and the reason of the other, one does not hinder but helps the other. Wherefore Gregory says (Moral. ii) that "the angels do not go abroad in such a manner as to lose the delights of inward contemplation."
Reply Obj. 4: In their external actions the angels chiefly minister to God, and secondarily to us; not because we are superior to them, absolutely speaking, but because, since every man or angel by cleaving to God is made one spirit with God, he is thereby superior to every creature. Hence the Apostle says (Phil. 2:3): "Esteeming others better than themselves." _______________________
SECOND ARTICLE [I, Q. 112, Art. 2]
Whether All the Angels Are Sent in Ministry?
Objection 1: It would seem that all the angels are sent in ministry. For the Apostle says (Heb. 1:14): "All are ministering spirits, sent to minister" [Vulg. 'Are they not all . . . ?'].
Obj. 2: Further, among the orders, the highest is that of the Seraphim, as stated above (Q. 108, A. 6). But a Seraph was sent to purify the lips of the prophet (Isa. 6:6, 7). Therefore much more are the inferior orders sent.
Obj. 3: Further, the Divine Persons infinitely excel all the angelic orders. But the Divine Persons are sent. Therefore much more are even the highest angels sent.
Obj. 4: Further, if the superior angels are not sent to the external ministries, this can only be because the superior angels execute the Divine ministries by means of the inferior angels. But as all the angels are unequal, as stated above (Q. 50, A. 4), each angel has an angel inferior to himself except the last one. Therefore only the last angel would be sent in ministry; which contradicts the words, "Thousands of thousands ministered to Him" (Dan. 7:10).