/summa/FP/FPX/FP_Q111:
We now consider the action of the angels on man, and inquire: (1) How far they can change them by their own natural power; (2) How they are sent by God to the ministry of men; (3) How they guard and protect men.
Under the first head there are four points of inquiry:
(1) Whether an angel can enlighten the human intellect?
(2) Whether he can change man's will?
(3) Whether he can change man's imagination?
(4) Whether he can change man's senses?