Again, abstraction from the external senses is not rendered necessary when the prophet's mind is enlightened by an intellectual light, or impressed with intelligible species, since in us the perfect judgment of the intellect is effected by its turning to sensible objects, which are the first principles of our knowledge, as stated in the First Part (Q. 84, A. 6).
When, however, prophetic revelation is conveyed by images in the imagination, abstraction from the senses is necessary lest the things thus seen in imagination be taken for objects of external sensation. Yet this abstraction from the senses is sometimes complete, so that a man perceives nothing with his senses; and sometimes it is incomplete, so that he perceives something with his senses, yet does not fully discern the things he perceives outwardly from those he sees in imagination. Hence Augustine says (Gen. ad lit. xii, 12): "Those images of bodies which are formed in the soul are seen just as bodily things themselves are seen by the body, so that we see with our eyes one who is present, and at the same time we see with the soul one who is absent, as though we saw him with our eyes."
Yet this abstraction from the senses takes place in the prophets without subverting the order of nature, as is the case with those who are possessed or out of their senses; but is due to some well-ordered cause. This cause may be natural—for instance, sleep—or spiritual—for instance, the intenseness of the prophets' contemplation; thus we read of Peter (Acts 10:9) that while he was praying in the supper-room [*Vulg.: 'the house-top' or 'upper-chamber'] "he fell into an ecstasy"—or he may be carried away by the Divine power, according to the saying of Ezechiel 1:3: "The hand of the Lord was upon him."
Reply Obj. 1: The passage quoted refers to prophets in whom imaginary pictures were formed or coordinated, either while asleep, which is denoted by the word "dream," or while awake, which is signified by the word "vision."
Reply Obj. 2: When the mind is intent, in its act, upon distant things which are far removed from the senses, the intensity of its application leads to abstraction from the senses; but when it is intent, in its act, upon the coordination of or judgment concerning objects of sense, there is no need for abstraction from the senses.
Reply Obj. 3: The movement of the prophetic mind results not from its own power, but from a power acting on it from above. Hence there is no abstraction from the senses when the prophet's mind is led to judge or coordinate matters relating to objects of sense, but only when the mind is raised to the contemplation of certain more lofty things.
Reply Obj. 4: The spirit of the prophets is said to be subject to the prophets as regards the prophetic utterances to which the Apostle refers in the words quoted; because, to wit, the prophets in declaring what they have seen speak their own mind, and are not thrown off their mental balance, like persons who are possessed, as Priscilla and Montanus maintained. But as regards the prophetic revelation itself, it would be more correct to say that the prophets are subject to the spirit of prophecy, i.e. to the prophetic gift. _______________________
FOURTH ARTICLE [II-II, Q. 173, Art. 4]
Whether Prophets Always Know the Things Which They Prophesy?
Objection 1: It would seem that the prophets always know the things which they prophesy. For, as Augustine says (Gen. ad lit. xii, 9), "those to whom signs were shown in spirit by means of the likenesses of bodily things, had not the gift of prophecy, unless the mind was brought into action, so that those signs were also understood by them." Now what is understood cannot be unknown. Therefore the prophet is not ignorant of what he prophesies.