Reply Obj. 1: Charity which makes man a friend of God, is a perfection of the will, in which God alone can form an impression; whereas prophecy is a perfection of the intellect, in which an angel also can form an impression, as stated in the First Part (Q. 111, A. 1), wherefore the comparison fails between the two.
Reply Obj. 2: The gratuitous graces are ascribed to the Holy Ghost as their first principle: yet He works grace of this kind in men by means of the angels.
Reply Obj. 3: The work of the instrument is ascribed to the principal agent by whose power the instrument acts. And since a minister is like an instrument, prophetic revelation, which is conveyed by the ministry of the angels, is said to be Divine. _______________________
THIRD ARTICLE [II-II, Q. 172, Art. 3]
Whether a Natural Disposition Is Requisite for Prophecy?
Objection 1: It would seem that a natural disposition is requisite for prophecy. For prophecy is received by the prophet according to the disposition of the recipient, since a gloss of Jerome on Amos 1:2, "The Lord will roar from Sion," says: "Anyone who wishes to make a comparison naturally turns to those things of which he has experience, and among which his life is spent. For example, sailors compare their enemies to the winds, and their losses to a shipwreck. In like manner Amos, who was a shepherd, likens the fear of God to that which is inspired by the lion's roar." Now that which is received by a thing according to the mode of the recipient requires a natural disposition. Therefore prophecy requires a natural disposition.
Obj. 2: Further, the considerations of prophecy are more lofty than those of acquired science. Now natural indisposition hinders the considerations of acquired science, since many are prevented by natural indisposition from succeeding to grasp the speculations of science. Much more therefore is a natural disposition requisite for the contemplation of prophecy.
Obj. 3: Further, natural indisposition is a much greater obstacle than an accidental impediment. Now the considerations of prophecy are hindered by an accidental occurrence. For Jerome says in his commentary on Matthew [*The quotation is from Origen, Hom. vi in Num.] that "at the time of the marriage act, the presence of the Holy Ghost will not be vouchsafed, even though it be a prophet that fulfils the duty of procreation." Much more therefore does a natural indisposition hinder prophecy; and thus it would seem that a good natural disposition is requisite for prophecy.
On the contrary, Gregory says in a homily for Pentecost (xxx in Ev.): "He," namely the Holy Ghost, "fills the boy harpist and makes him a Psalmist; He fills the herdsman plucking wild figs, and makes him a prophet." Therefore prophecy requires no previous disposition, but depends on the will alone of the Holy Ghost, of Whom it is written (1 Cor. 12:2): "All these things, one and the same Spirit worketh, dividing to every one according as He will."
I answer that, As stated above (A. 1), prophecy in its true and exact sense comes from Divine inspiration; while that which comes from a natural cause is not called prophecy except in a relative sense. Now we must observe that as God Who is the universal efficient cause requires neither previous matter nor previous disposition of matter in His corporeal effects, for He is able at the same instant to bring into being matter and disposition and form, so neither does He require a previous disposition in His spiritual effects, but is able to produce both the spiritual effect and at the same time the fitting disposition as requisite according to the order of nature. More than this, He is able at the same time, by creation, to produce the subject, so as to dispose a soul for prophecy and give it the prophetic grace, at the very instant of its creation.