On Christ's Conquest of the Passions

Thus, in His love of humanity, the only-begotten Son and Logos of God became perfect man, with a view to reedeming human nature from this helplessness in evil. Taking on the original condition of Adam as he was in the very beginning, he was sinless but not incorruptible, and he assumed, from the procreative process introduced into human nature as a consequence of sin, only the liability to passions, not the sin itself. Since then, through the liability to passions that resulted from Adam's sin, the evil powers, as I already said, have hidden their activities clandestinely under the law of human nature in its current circumstance, it merely follows that these wicked powers- seeing in God our Savior the same natural liability to passions as in Adam, since he was in the flesh, and thinking that he was necessarily and circumstantially a mere man, that the Lord himself had to submit to the law of nature, that he acted by deliberation rather than true volition- assailed him. These evil powers hoped to use natural passibility to induce even the Lord himself to fantasize unnatural passions and to do what suited them. They tried to do this to him who, in his first experience of temptation by pleasure, subjected himself to being deluded by these evil powers' deceits, only to put off those powers by elimiating them from human nature, remaining unapproachable and untouchable for them. Clearly he won the victory over them for our sake, not his own; and it was for us that he became man and, in his goodness, inaugurated a complete restoration.

St. Maximus Confessor, Ad Thalassium 21

From On the Cosmic Mystery of Jesus Christ