Whether all the angels are sent in ministry?

Objections

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 . . . ?'].
Objection 2 : Further, among the orders, the highest is that of the Seraphim, as stated above (Question [108], Article [6]). But a Seraph was sent to purify the lips of the prophet (Is. 6:6,7). Therefore much more are the inferior orders sent.
Objection 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.
Objection 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 (Question [50], Article [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).