City of God

The devils themselves knew this manifestation of God so well, that they said to the Lord though clothed with the infirmity of flesh, “What have we to do with You, Jesus of Nazareth? Have You come to destroy us before the time?” From these words, it is clear that they had great knowledge, and no charity. They feared His power to punish, and did not love His righteousness. He made known to them so much as He pleased, and He was pleased to make known so much as was needful. But He made Himself known not as to the holy angels, who know Him as the Word of God, and rejoice in His eternity, which they partake, but as was requisite to strike with terror the beings from whose tyranny He was going to free those who were predestined to His kingdom and the glory of it, eternally true and truly eternal.

He made Himself known, therefore, to the demons, not by that which is life eternal, and the unchangeable light which illumines the pious, whose souls are cleansed by the faith that is in Him, but by some temporal effects of His power, and evidences of His mysterious presence, which were more easily discerned by the angelic senses even of wicked spirits than by human infirmity. But when He judged it advisable gradually to suppress these signs, and to retire into deeper obscurity, the prince of the demons doubted whether He were the Christ, and endeavored to ascertain this by tempting Him, in so far as He permitted Himself to be tempted, that He might adapt the manhood He wore to be an example for our imitation.

But after that temptation, when, as Scripture says, He was ministered to by the angels who are good and holy, and therefore objects of terror to the impure spirits, He revealed more and more distinctly to the demons how great He was, so that, even though the infirmity of His flesh might seem contemptible, none dared to resist His authority.