and command of God.

The apparitions of a spirit, or of an angel and a demon, which show
themselves clothed in an apparent body, and only as a shadow or a
phantom, as that of the angel who showed himself to Manoah the father
of Samson, and vanished with the smoke of the sacrifice, and of him
who extricated St. Peter from prison, and disappeared in the same way
after having conducted him the length of a street; the bodies which
these angels assumed, and which we suppose to have been only apparent
and aerial, present great difficulties; for either those bodies were
their own, or they were assumed or borrowed.

If those forms were their own, and we suppose with several ancient and
some new writers that angels, demons, and even human souls have a kind
of subtile, transparent, and aerial body, the difficulty lies in
knowing how they can condense the transparent body, and render it
visible when it was before invisible; for if it was always and
naturally evident to the senses and visible, there would be another
kind of continual miracle to render it invisible, and hide it from our
sight; and if of its nature it is invisible, what might can render it
visible? On whatever side we regard this object it seems equally
miraculous, whether to make evident to the senses that which is purely
spiritual, or to render invisible that which in its nature is palpable
and corporeal.

The ancient fathers of the church, who gave to angels subtile bodies
of an airy nature, explained, according to their principles, more
easily the predictions made by the demons, and the wonderful
operations which they cause in the air, in the elements, in our
bodies, and which are far beyond what the cleverest and the most
learned men can know, predict, and perform. They likewise conceived
more easily that evil angels can cause maladies, render the air impure
and contagious, that they inspire the wicked with wrong thoughts and
unjust desires, that they can penetrate our thoughts and wishes, that
they foresee tempests and changes in the air, and derangements in the
seasons; all that can be explained with much more facility on the
hypothesis that demons have bodies composed of very fine and subtile
air.

St. Augustine[440] had written that they could also discover what is
passing in our mind, and at the bottom of our heart, not only by our
words, but also by certain signs and movements, which escape from the
most circumspect; but reflecting on what he had adv