Objection 1. It would seem that the proofs which Christ made use of did not sufficiently manifest the truth of His Resurrection. For after the Resurrection Christ showed nothing to His disciples which angels appearing to men did not or could not show; because angels have frequently shown themselves to men under human aspect, have spoken and lived with them, and eaten with them, just as if they were truly men, as is evident from Genesis 18, of the angels whom Abraham entertained, and in the Book of Tobias, of the angel who "conducted" him "and brought" him back. Nevertheless, angels have not true bodies naturally united to them; which is required for a resurrection. Consequently, the signs which Christ showed His disciples were not sufficient for manifesting His Resurrection.
Objection 2. Further, Christ rose again gloriously, that is, having a human nature with glory. But some of the things which Christ showed to His disciples seem contrary to human nature, as for instance, that "He vanished out of their sight," and entered in among them "when the doors were shut": and some other things seem contrary to glory, as for instance, that He ate and drank, and bore the scars of His wounds. Consequently, it seems that those proofs were neither sufficient nor fitting for establishing faith in the Resurrection.
Objection 3. Further, after the Resurrection Christ's body was such that it ought not to be touched by mortal man; hence He said to Magdalen (John 20:17): "Do not touch Me; for I am not yet ascended to My Father." Consequently, it was not fitting for manifesting the truth of His Resurrection, that He should permit Himself to be handled by His disciples.
Objection 4. Further, clarity seems to be the principal of the qualities of a glorified body: yet He gave no sign thereof in His Resurrection. Therefore it seems that those proofs were insufficient for showing the quality of Christ's Resurrection.
Objection 5. [This objection is wanting in the older codices, and in the text of the Leonine edition, which, however, gives it in a note as taken from one of the more recent codices of the Vatican.]
Further, the angels introduced as witnesses for the Resurrection seem insufficient from the want of agreement on the part of the Evangelists. Because in Matthew's account the angel is described as sitting upon the stone rolled back, while Mark states that he was seen after the women had entered the tomb; and again, whereas these mention one angel, John says that there were two sitting, and Luke says that there were two standing. Consequently, the arguments for the Resurrection do not seem to agree.
On the contrary, Christ, who is the Wisdom of God, "ordereth all things sweetly" and in a fitting manner, according to Wisdom 8:1.
I answer that, Christ manifested His Resurrection in two ways: namely, by testimony; and by proof or sign: and each manifestation was sufficient in its own class. For in order to manifest His Resurrection He made use of a double testimony, neither of which can be rebutted. The first of these was the angels' testimony, who announced the Resurrection to the women, as is seen in all the Evangelists: the other was the testimony of the Scriptures, which He set before them to show the truth of the Resurrection, as is narrated in the last chapter of Luke.
Again, the proofs were sufficient for showing that the Resurrection was both true and glorious. That it was a true Resurrection He shows first on the part of the body; and this He shows in three respects; first of all, that it was a true and solid body, and not phantastic or rarefied, like the air. And He establishes this by offering His body to be handled; hence He says in the last chapter of Luke (39): "Handle and see; for a spirit hath not flesh and bones, as you see Me to have." Secondly, He shows that it was a human body, by presenting His true features for them to behold. Thirdly, He shows that it was identically the same body which He had before, by showing them the scars of the wounds; hence, as we read in the last chapter of Luke (39) he said to them: "See My hands and feet, that it is I Myself."
Secondly, He showed them the truth of His Resurrection on the part of His soul reunited with His body: and He showed this by the works of the threefold life. First of all, in the operations of the nutritive life, by eating and drinking with His disciples, as we read in the last chapter of Luke. Secondly, in the works of the sensitive life, by replying to His disciples' questions, and by greeting them when they were in His presence, showing thereby that He both saw and heard; thirdly, in the works of the intellective life by their conversing with Him, and discoursing on the Scriptures. And, in order that nothing might be wanting to make the manifestation complete, He also showed that He had the Divine Nature, by working the miracle of the draught of fishes, and further by ascending into heaven while they were beholding Him: because, according to John 3:13: "No man hath ascended into heaven, but He that descended from heaven, the Son of Man who is in heaven."
He also showed His disciples the glory of His Resurrection by entering in among them when the doors were closed: as Gregory says (Hom. xxvi in Evang.): "Our Lord allowed them to handle His flesh which He had brought through closed doors, to show that His body was of the same nature but of different glory." It likewise was part of the property of glory that "He vanished suddenly from their eyes," as related in the last chapter of Luke; because thereby it was shown that it lay in His power to be seen or not seen; and this belongs to a glorified body, as stated above (54, 1, ad 2, 2, ad 1).
Reply to Objection 1. Each separate argument would not suffice of itself for showing perfectly Christ's Resurrection, yet all taken collectively establish it completely, especially owing to the testimonies of the Scriptures, the sayings of the angels, and even Christ's own assertion supported by miracles. As to the angels who appeared, they did not say they were men, as Christ asserted that He was truly a man. Moreover, the manner of eating was different in Christ and the angels: for since the bodies assumed by the angels were neither living nor animated, there was no true eating, although the food was really masticated and passed into the interior of the assumed body: hence the angels said to Tobias (12:18-19): "When I was with you... I seemed indeed to eat and drink with you; but I use an invisible meat." But since Christ's body was truly animated, His eating was genuine. For, as Augustine observes (De Civ. Dei xiii), "it is not the power but the need of eating that shall be taken away from the bodies of them who rise again." Hence Bede says on Luke 24:41: "Christ ate because He could, not because He needed."
Reply to Objection 2. As was observed above, some proofs were employed by Christ to prove the truth of His human nature, and others to show forth His glory in rising again. But the condition of human nature, as considered in itself, namely, as to its present state, is opposite to the condition of glory, as is said in 1 Corinthians 15:43: "It is sown in weakness, it shall rise in power." Consequently, the proofs brought forward for showing the condition of glory, seem to be in opposition to nature, not absolutely, but according to the present state, and conversely. Hence Gregory says (Hom. xxvi in Evang.): "The Lord manifested two wonders, which are mutually contrary according to human reason, when after the Resurrection He showed His body as incorruptible and at the same time palpable."
Reply to Objection 3. As Augustine says (Tract. cxxi super Joan.), "these words of our Lord, 'Do not touch Me, for I am not yet ascended to My Father,'" show "that in that woman there is a figure of the Church of the Gentiles, which did not believe in Christ until He was ascended to the Father. Or Jesus would have men to believe in Him, i.e. to touch Him spiritually, as being Himself one with the Father. For to that man's innermost perceptions He is, in some sort, ascended unto the Father, who has become so far proficient in Him, as to recognize in Him the equal with the Father... whereas she as yet believed in Him but carnally, since she wept for Him as for a man." But when one reads elsewhere of Mary having touched Him, when with the other women, she "'came up and took hold of His feet,' that matters little," as Severianus says [Chrysologus, Serm. lxxvi, "for, the first act relates to figure, the other to sex; the former is of Divine grace, the latter of human nature." Or as Chrysostom says (Hom. lxxxvi in Joan.): "This woman wanted to converse with Christ just as before the Passion, and out of joy was thinking of nothing great, although Christ's flesh had become much nobler by rising again." And therefore He said: "I have not yet ascended to My Father"; as if to say: "Do not suppose I am leading an earthly life; for if you see Me upon earth, it is because I have not yet ascended to My Father, but I am going to ascend shortly." Hence He goes on to say: "I ascend to My Father, and to your Father."
Reply to Objection 4. As Augustine says ad Orosium (Dial. lxv, Qq.): "Our Lord rose in clarified flesh; yet He did not wish to appear before the disciples in that condition of clarity, because their eyes could not gaze upon that brilliancy. For if before He died for us and rose again the disciples could not look upon Him when He was transfigured upon the mountain, how much less were they able to gaze upon Him when our Lord's flesh was glorified." It must also be borne in mind that after His Resurrection our Lord wished especially to show that He was the same as had died; which the manifestation of His brightness would have hindered considerably: because change of features shows more than anything else the difference in the person seen: and this is because sight specially judges of the common sensibles, among which is one and many, or the same and different. But before the Passion, lest His disciples might despise its weakness, Christ meant to show them the glory of His majesty; and this the brightness of the body specially indicates. Consequently, before the Passion He showed the disciples His glory by brightness, but after the Resurrection by other tokens.
Reply to Objection 5. As Augustine says (De Consens. Evang. iii): "We can understand one angel to have been seen by the women, according to both Matthew and Mark, if we take them as having entered the sepulchre, that is, into some sort of walled enclosure, and that there they saw an angel sitting upon the stone which was rolled back from the monument, as Matthew says; and that this is Mark's expression--'sitting on the right side'; afterwards when they scanned the spot where the Lord's body had lain, they beheld two angels, who were at first seated, as John says, and who afterwards rose so as to be seen standing, as Luke relates."
Source: Summa Theologica (New Advent)