At that time Jesus was led by the Spirit into the desert, to be tempted by the devil. Mt. 4:1

Lent is only four days old, and already we are brought to our first gut check. Those voluntary penances we have embraced– the Spirit, as it were, leading us into the desert– are they onerous? And are we already tempted to be lax in their observance?

I used to wonder why Jesus would allow Himself to be tempted, and whether He could really be tempted if it were impossible for Him to sin.

As usual, St. Thomas Aquinas has the answer, and states in the Summa Theologica, Question 41, Article 1:

Christ came to destroy the works of the devil, not by powerful deeds, but rather by suffering from him and his members, so as to conquer the devil by righteousness, not by power; thus Augustine says (De Trin. xiii) that “the devil was to be overcome, not by the power of God, but by righteousness.” And therefore in regard to Christ’s temptation we must consider what He did of His own will and what He suffered from the devil. For that He allowed Himself to be tempted was due to His own will. Wherefore it is written (Matthew 4:1): “Jesus was led by the Spirit into the desert, to be tempted by the devil”; and Gregory (Hom. xvi in Evang.) says this is to be understood of the Holy Ghost, to wit, that “thither did His Spirit lead Him, where the wicked spirit would find Him and tempt Him.” But He suffered from the devil in being “taken up” on to “the pinnacle of the Temple” and again “into a very high mountain.” Nor is it strange, as Gregory observes, “that He allowed Himself to be taken by him on to a mountain, who allowed Himself to be crucified by His members.” And we understand Him to have been taken up by the devil, not, as it were, by force, but because, as Origen says (Hom. xxi super Luc.), “He followed Him in the course of His temptation like a wrestler advancing of his own accord.”

Later, in Article 2, St. Thomas writes:

The occasions of temptation are twofold. one is on the part of man—for instance, when a man causes himself to be near to sin by not avoiding the occasion of sinning. And such occasions of temptation should be avoided, as it is written of Lot (Gn. 19:17): “Neither stay thou in all the country about” Sodom.

Another occasion of temptation is on the part of the devil, who always “envies those who strive for better things,” as Ambrose says (In Luc. iv, 1). And such occasions of temptation are not to be avoided. Hence Chrysostom says (Hom. v in Matth. [*From the supposititious Opus Imperfectum]): “Not only Christ was led into the desert by the Spirit, but all God’s children that have the Holy Ghost. For it is not enough for them to sit idle; the Holy Ghost urges them to endeavor to do something great: which is for them to be in the desert from the devil’s standpoint, for no unrighteousness, in which the devil delights, is there. Again, every good work, compared to the flesh and the world, is the desert; because it is not according to the will of the flesh and of the world.” Now, there is no danger in giving the devil such an occasion of temptation; since the help of the Holy Ghost, who is the Author of the perfect deed, is more powerful* than the assault of the envious devil.

Finally, in Article 3:

It was becoming that Christ should wish to fast before His temptation. First, in order to give us an example. For since we are all in urgent need of strengthening ourselves against temptation, as stated above (A[1]), by fasting before being tempted, He teaches us the need of fasting in order to equip ourselves against temptation. Hence the Apostle (2 Cor. 6:5,7) reckons “fastings” together with the “armor of justice.”

Secondly, in order to show that the devil assails with temptations even those who fast, as likewise those who are given to other good works. And so Christ’s temptation took place after His fast, as also after His baptism. Hence since rather Chrysostom says (Hom. xiii super Matth.): “To instruct thee how great a good is fasting, and how it is a most powerful shield against the devil; and that after baptism thou shouldst give thyself up, not to luxury, but to fasting; for this cause Christ fasted, not as needing it Himself, but as teaching us.”

Let us call upon Christ, the Victor over temptation, sin and the devil, to strengthen us to persevere in our Lenten fasting. May he assist us not only to persevere in fasting, but to fast for a holy purpose– that we grow in holiness and perfection, and make reparation for our sins. If we persevere, we are given the promise of Divine assistance, for we can expect what Christ Himself received. “And behold Angels came, and ministered to Him.” Mt. 4.11