I answer that, The temptation which comes from the enemy takes the form of a suggestion, as Gregory says (Hom. xvi in Evang.). Now a suggestion cannot be made to everybody in the same way; it must arise from those things towards which each one has an inclination. Consequently the devil does not straight away tempt the spiritual man to grave sins, but he begins with lighter sins, so as gradually to lead him to those of greater magnitude. Wherefore Gregory (Moral. xxxi), expounding Job 39:25, “He smelleth the battle afar off, the encouraging of the captains and the shouting of the army,” says: “The captains are fittingly described as encouraging, and the army as shouting. Because vices begin by insinuating themselves into the mind under some specious pretext: then they come on the mind in such numbers as to drag it into all sorts of folly, deafening it with their bestial clamor.”
Thus, too, did the devil set about the temptation of the first man. For at first he enticed his mind to consent to the eating of the forbidden fruit, saying (Genesis 3:1): “Why hath God commanded you that you should not eat of every tree of paradise?” Secondly [he tempted him] to vainglory by saying: “Your eyes shall be opened.” Thirdly, he led the temptation to the extreme height of pride, saying: “You shall be as gods, knowing good and evil.” This same order did he observe in tempting Christ. For at first he tempted Him to that which men desire, however spiritual they may be–namely, the support of the corporeal nature by food. Secondly, he advanced to that matter in which spiritual men are sometimes found wanting, inasmuch as they do certain things for show, which pertains to vainglory. Thirdly, he led the temptation on to that in which no spiritual men, but only carnal men, have a part–namely, to desire worldly riches and fame, to the extent of holding God in contempt. And so in the first two temptations he said: “If Thou be the Son of God”; but not in the third, which is inapplicable to spiritual men, who are sons of God by adoption, whereas it does apply to the two preceding temptations.
And Christ resisted these temptations by quoting the authority of the Law, not by enforcing His power, “so as to give more honor to His human nature and a greater punishment to His adversary, since the foe of the human race was vanquished, not as by God, but as by man”; as Pope Leo says (Serm. 1, De Quadrag. 3).