On the fact that the power to hurt does not depend upon the will of the devils.
But that they have not the power of hurting any man is shown in a very clear way by the instance of the blessed Job, where the enemy did not venture to try him beyond what was allowed to him by the Divine permission; and it is evidenced by the confession of the same spirits contained in the records of the gospel, where they say: “If Thou cast us out, suffer us to go into the herd of swine.” 1487 And far more must we hold that they cannot of their own free will enter into any one of men who are created in the image of God, if they have not power to enter into dumb and unclean animals without the permission of God. But no one—I will not say of the younger men, whom we see living most steadfastly in this desert, but even of those who are perfect—could live alone in the desert, surrounded by such swarms of foes of this kind, if they had unlimited power and freedom to hurt and tempt us: and still more clearly is this supported by the words of our Lord and Saviour, which in the lowliness of the manhood He had assumed, He uttered to Pilate, when He said: “Thou couldest have no power against Me at all, unless it were given thee from above.” 1488
S. Matt. viii. 31.370:1488
S. John xix. 11.