ngel,
as explained above (Q. 106, A. 1).

The human intellect, however, cannot grasp the universal truth itself
unveiled; because its nature requires it to understand by turning to
the phantasms, as above explained (Q. 84, A. 7). So the angels
propose the intelligible truth to men under the similitudes of
sensible things, according to what Dionysius says (Coel. Hier. i),
that, "It is impossible for the divine ray to shine on us, otherwise
than shrouded by the variety of the sacred veils." On the other hand,
the human intellect as the inferior, is strengthened by the action of
the angelic intellect. And in these two ways man is enlightened by an
angel.

Reply Obj. 1: Two dispositions concur in the virtue of faith; first,
the habit of the intellect whereby it is disposed to obey the will
tending to Divine truth. For the intellect assents to the truth of
faith, not as convinced by the reason, but as commanded by the will;
hence Augustine says, "No one believes except willingly." In this
respect faith comes from God alone. Secondly, faith requires that
what is to be believed be proposed to the believer; which is
accomplished by man, according to Rom. 10:17, "Faith cometh by
hearing"; principally, however, by the angels, by whom Divine things
are revealed to men. Hence the angels have some part in the
enlightenment of faith. Moreover, men are enlightened by the angels
not only concerning what is to be believed; but also as regards what
is to be done.

Reply Obj. 2: Natural reason, which is immediately from God, can be
strengthened by an angel, as we have said above. Again, the more the
human intellect is strengthened, so much higher an intelligible truth
can be elicited from the species derived from creatures. Thus man is
assisted by an angel so that he may obtain from creatures a more
perfect knowledge of God.

Reply Obj. 3: Intellectual operation and enlightenment can be
understood in two ways. First, on the part of the object understood;
thus whoever understands or is enlightened, knows that he understands
or is enlightened, because he knows that the object is made known to
him. Secondly, on the part of the principle; and thus it does not
follow that whoever understands a truth, knows what the intellect is,
which is the principle of the intellectual operation. In like manner
not everyone who is enlightened by an angel, knows that he is
enlightened by him.
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SECOND ARTICLE [I, Q. 111, Art. 3