Objection 1. It would seem that Christ worked miracles unfittingly on men. For in man the soul is of more import than the body. Now Christ worked many miracles on bodies, but we do not read of His working any miracles on souls: for neither did He convert any unbelievers to the faith mightily, but by persuading and convincing them with outward miracles, nor is it related of Him that He made wise men out of fools. Therefore it seems that He worked miracles on men in an unfitting manner.
Objection 2. Further, as stated above (Question 43, Article 2), Christ worked miracles by Divine power: to which it is proper to work suddenly, perfectly, and without any assistance. Now Christ did not always heal men suddenly as to their bodies: for it is written (Mark 8:22-25) that, "taking the blind man by the hand, He led him out of the town; and, spitting upon his eyes, laying His hands on him, He asked him if he saw anything. And, looking up, he said: I see men as it were trees walking. After that again He laid His hands upon his eyes, and he began to see, and was restored, so that he saw all things clearly." It is clear from this that He did not heal him suddenly, but at first imperfectly, and by means of His spittle. Therefore it seems that He worked miracles on men unfittingly.
Objection 3. Further, there is no need to remove at the same time things which do not follow from one another. Now bodily ailments are not always the result of sin, as appears from our Lord's words (John 9:3): "Neither hath this man sinned, nor his parents, that he should be born blind." It was unseemly, therefore, for Him to forgive the sins of those who sought the healing of the body, as He is related to have done in the case of the man sick of the palsy (Matthew 9:2): the more that the healing of the body, being of less account than the forgiveness of sins, does not seem a sufficient argument for the power of forgiving sins.
Objection 4. Further, Christ's miracles were worked in order to confirm His doctrine, and witness to His Godhead, as stated above (Question 43, Article 4). Now no man should hinder the purpose of his own work. Therefore it seems unfitting that Christ commanded those who had been healed miraculously to tell no one, as appears from Matthew 9:30 and Mark 8:26: the more so, since He commanded others to proclaim the miracles worked on them; thus it is related (Mark 5:19) that, after delivering a man from the demons, He said to him: "Go into thy house to thy friends, and tell them, how great things the Lord hath done for thee."
On the contrary, It is written (Mark 7:37): "He hath done all things well: He hath made both the deaf to hear and the dumb to speak."
I answer that, The means should be proportionate to the end. Now Christ came into the world and taught in order to save man, according to John 3:17: "For God sent not His Son into the world to judge the world, but that the world may be saved by Him." Therefore it was fitting that Christ, by miraculously healing men in particular, should prove Himself to be the universal and spiritual Saviour of all.
Reply to Objection 1. The means are distinct from the end. Now the end for which Christ's miracles were worked was the health of the rational part, which is healed by the light of wisdom, and the gift of righteousness: the former of which presupposes the latter, since, as it is written (Wisdom 1:4): "Wisdom will not enter into a malicious soul, nor dwell in a body subject to sins." Now it was unfitting that man should be made righteous unless he willed: for this would be both against the nature of righteousness, which implies rectitude of the will, and contrary to the very nature of man, which requires to be led to good by the free-will, not by force. Christ, therefore, justified man inwardly by the Divine power, but not against man's will. Nor did this pertain to His miracles, but to the end of His miracles. In like manner by the Divine power He infused wisdom into the simple minds of His disciples: hence He said to them (Luke 21:15): "I will give you a mouth and wisdom" which "all your adversaries will not be able to resist and gainsay." And this, in so far as the enlightenment was inward, is not to be reckoned as a miracle, but only as regards the outward action--namely, in so far as men saw that those who had been unlettered and simple spoke with such wisdom and constancy. Wherefore it is written (Acts 4:13) that the Jews, "seeing the constancy of Peter and of John, understanding that they were illiterate and ignorant men... wondered."--And though such like spiritual effects are different from visible miracles, yet do they testify to Christ's doctrine and power, according to Hebrews 2:4: "God also bearing them witness by signs and wonders and divers miracles, and distributions of the Holy Ghost."
Nevertheless Christ did work some miracles on the soul of man, principally by changing its lower powers. Hence Jerome, commenting on Matthew 9:9, "He rose up and followed Him," says: "Such was the splendor and majesty of His hidden Godhead, which shone forth even in His human countenance, that those who gazed on it were drawn to Him at first sight." And on Matthew 21:12, "(Jesus) cast out all them that sold and bought," the same Jerome says: "Of all the signs worked by our Lord, this seems to me the most wondrous--that one man, at that time despised, could, with the blows of one scourge, cast out such a multitude. For a fiery and heavenly light flashed from His eyes, and the majesty of His Godhead shone in His countenance." And Origen says on John 2:15 that "this was a greater miracle than when He changed water into wine, for there He shows His power over inanimate matter, whereas here He tames the minds of thousands of men." Again, on John 18:6, "They went backward and fell to the ground," Augustine says: "Though that crowd was fierce in hate and terrible with arms, yet did that one word... without any weapon, smite them through, drive them back, lay them prostrate: for God lay hidden in that flesh." Moreover, to this must be referred what Luke says (4:30) -- namely, that Jesus, "passing through the midst of them, went His way," on which Chrysostom observes (Hom. xlviii in Joan.): "That He stood in the midst of those who were lying in wait for Him, and was not seized by them, shows the power of His Godhead"; and, again, that which is written John 8:59, "Jesus hid Himself and went out of the Temple," on which Theophylact says: "He did not hide Himself in a corner of the Temple, as if afraid, or take shelter behind a wall or pillar; but by His heavenly power making Himself invisible to those who were threatening Him, He passed through the midst of them."
From all these instances it is clear that Christ, when He willed, changed the minds of men by His Divine power, not only by the bestowal of righteousness and the infusion of wisdom, which pertains to the end of miracles, but also by outwardly drawing men to Himself, or by terrifying or stupefying them, which pertains to the miraculous itself.
Reply to Objection 2. Christ came to save the world, not only by Divine power, but also through the mystery of His Incarnation. Consequently in healing the sick He frequently not only made use of His Divine power, healing by way of command, but also by applying something pertaining to His human nature. Hence on Luke 4:40, "He, laying His hands on every one of them, healed them," Cyril says: "Although, as God, He might, by one word, have driven out all diseases, yet He touched them, showing that His own flesh was endowed with a healing virtue." And on Mark 8:23, "Spitting upon his eyes, laying His hands on him," etc., Chrysostom [Victor of Antioch] says: "He spat and laid His hands upon the blind man, wishing to show that His Divine word, accompanied by His operation, works wonders: for the hand signifies operation; the spittle signifies the word which proceeds from the mouth." Again, on John 9:6, "He made clay of the spittle, and spread the clay upon the eyes of the blind man," Augustine says: "Of His spittle He made clay--because 'the Word was made flesh.'" Or, again, as Chrysostom says, to signify that it was He who made man of "the slime of the earth."
It is furthermore to be observed concerning Christ's miracles that generally what He did was most perfect. Hence on John 2:10, "Every man at first setteth forth good wine," Chrysostom says: "Christ's miracles are such as to far surpass the works of nature in splendor and usefulness." Likewise in an instant He conferred perfect health on the sick. Hence on Matthew 8:15, "She arose and ministered to them," Jerome says: "Health restored by our Lord returns wholly and instantly."
There was, however, special reason for the contrary happening in the case of the man born blind, and this was his want of faith, as Chrysostom [Victor of Antioch] says. Or as Bede observes on Mark 8:23: "Whom He might have healed wholly and instantly by a single word, He heals little by little, to show the extent of human blindness, which hardly, and that only by degrees, can come back to the light: and to point out that each step forward in the way of perfection is due to the help of His grace."
Reply to Objection 3. As stated above (Question 43, Article 2), Christ worked miracles by Divine power. Now "the works of God are perfect" (Deuteronomy 32:4). But nothing is perfect except it attain its end. Now the end of the outward healing worked by Christ is the healing of the soul. Consequently it was not fitting that Christ should heal a man's body without healing his soul. Wherefore on John 7:23, "I have healed the whole man on a Sabbath day," Augustine says: "Because he was cured, so as to be whole in body; he believed, so as to be whole in soul." To the man sick of the palsy it is said specially, "Thy sins are forgiven thee," because, as Jerome observes on Matthew 9:5-6: "We are hereby given to understand that ailments of the body are frequently due to sin: for which reason, perhaps, first are his sins forgiven, that the cause of the ailment being removed, health may return." Wherefore, also (John 4:14), it is said: "Sin no more, lest some worse thing happen to thee." Whence, says Chrysostom, "we learn that his sickness was the result of sin."
Nevertheless, as Chrysostom says on Matthew 9:5: "By how much a soul is of more account than a body, by so much is the forgiving of sins a greater work than healing the body; but because the one is unseen He does the lesser and more manifest thing in order to prove the greater and more unseen."
Reply to Objection 4. On Matthew 9:30, "See that no man know this," Chrysostom says: "If in another place we find Him saying, 'Go and declare the glory of God' (cf. Mark 5:19; Luke 8:39), that is not contrary to this. For He instructs us to forbid them that would praise us on our own account: but if the glory be referred to God, then we must not forbid, but command, that it be done."
Source: Summa Theologica (New Advent)