Objection 1. It seems that the bodies of the saints will not be impassible after the resurrection. For everything mortal is passible. But man, after the resurrection, will be "a mortal rational animal," for such is the definition of man, which will never be dissociated from him. Therefore the body will be passible.
Objection 2. Further, whatever is in potentiality to have the form of another thing is passible in relation to something else; for this is what is meant by being passive to another thing (De Gener. i). Now the bodies of the saints will be in potentiality to the form of another thing after the resurrection; since matter, according as it is under one form, does not lose its potentiality to another form. But the bodies of the saints after the resurrection will have matter in common with the elements, because they will be restored out of the same matter of which they are now composed. Therefore they will be in potentiality to another form, and thus will be passible.
Objection 3. Further, according to the Philosopher (De Gener. i), contraries have a natural inclination to be active and passive towards one another. Now the bodies of the saints will be composed of contraries after the resurrection, even as now. Therefore they will be passible.
Objection 4. Further, in the human body the blood and humors will rise again, as stated above (80, 3,4). Now, sickness and such like passions arise in the body through the antipathy of the humors. Therefore the bodies of the saints will be passible after the resurrection.
Objection 5. Further, actual defect is more inconsistent with perfection than potential defect. But passibility denotes merely potential defect. Since then there will be certain actual defects in the bodies of the blessed, such as the scars of the wounds in the martyrs, even as they were in Christ, it would seem that their perfections will not suffer, if we grant their bodies to be passible.
On the contrary, Everything passible is corruptible, because "increase of passion results in loss of substance" [Aristotle, Topic. vi, 1. Now the bodies of the saints will be incorruptible after the resurrection, according to 1 Corinthians 15:42, "It is sown in corruption, it shall rise in incorruption." Therefore they will be impassible.
Further, the stronger is not passive to the weaker. But no body will be stronger than the bodies of the saints, of which it is written (1 Corinthians 15:43): "It is sown in weakness, it shall rise in power." Therefore they will be impassible.
I answer that, We speak of a thing being "passive" in two ways [Cf. I-II, 22, 1]. First in a broad sense, and thus every reception is called a passion, whether the thing received be fitting to the receiver and perfect it, or contrary to it and corrupt it. The glorious bodies are not said to be impassible by the removal of this kind of passion, since nothing pertaining to perfection is to be removed from them. In another way we use the word "passive" properly, and thus the Damascene defines passion (De Fide Orth. ii, 22) as being "a movement contrary to nature." Hence an immoderate movement of the heart is called its passion, but a moderate movement is called its operation. The reason of this is that whatever is patient is drawn to the bounds of the agent, since the agent assimilates the patient to itself, so that, therefore, the patient as such is drawn beyond its own bounds within which it was confined. Accordingly taking passion in its proper sense there will be no potentiality to passion in the bodies of the saints after resurrection; wherefore they are said to be impassible.
The reason however of this impassibility is assigned differently by different persons. Some ascribe it to the condition of the elements, which will be different then from what it is now. For they say that the elements will remain, then, as to substance, yet that they will be deprived of their active and passive qualities. But this does not seem to be true: because the active and passive qualities belong to the perfection of the elements, so that if the elements were restored without them in the body of the man that rises again, they would be less perfect than now. Moreover since these qualities are the proper accidents of the elements, being caused by their form and matter, it would seem most absurd for the cause to remain and the effect to be removed. Wherefore others say that the qualities will remain, but deprived of their proper activities, the Divine power so doing for the preservation of the human body. This however would seem to be untenable, since the action and passion of the active and passive qualities is necessary for the mixture (of the elements), and according as one or the other preponderates the mixed (bodies) differ in their respective complexions, and this must apply to the bodies of those who rise again, for they will contain flesh and bones and like parts, all of which demand different complexions. Moreover, according to this, impassibility could not be one of their gifts, because it would not imply a disposition in the impassible substance, but merely an external preventive to passion, namely the power of God, which might produce the same effect in a human body even in this state of life. Consequently others say that in the body itself there will be something preventing the passion of a glorified body, namely the nature of a fifth [The other four being the elements; this fifth element was known to the peripatetic philosophers as the quintessence, of which they held heavenly bodies to be formed]: or heavenly body, which they maintain enters into the composition of a human body, to the effect of blending the elements together in harmony so as to be fitting matter for the rational soul; but that in this state of life, on account of the preponderance of the elemental nature, the human body is passible like other elements, whereas in the resurrection the nature of the fifth body will predominate, so that the human body will be made impassible in likeness to the heavenly body. But this cannot stand, because the fifth body does not enter materially into the composition of a human body, as was proved above (Sent. ii, D, 12, Q. 1, 1). Moreover it is absurd to say that a natural power, such as the power of a heavenly body, should endow the human body with a property of glory, such as the impassibility of a glorified body, since the Apostle ascribes to Christ's power the transformation of the human body, because "such as is the heavenly, such also are they that are heavenly" (1 Corinthians 15:48), and "He will reform the body of our lowness, made like to the body of His glory, according to the operation whereby also He is able to subdue all things unto Himself" (Philippians 3:21). And again, a heavenly nature cannot exercise such power over the human body as to take from it its elemental nature which is passible by reason of its essential constituents. Consequently we must say otherwise that all passion results from the agent overcoming the patient, else it would not draw it to its own bounds. Now it is impossible for agent to overcome patient except through the weakening of the hold which the form of the patient has over its matter, if we speak of the passion which is against nature, for it is of passion in this sense that we are speaking now: for matter is not subject to one of two contraries, except through the cessation or at least the diminution of the hold which the other contrary has on it. Now the human body and all that it contains will be perfectly subject to the rational soul, even as the soul will be perfectly subject to God. Wherefore it will be impossible for the glorified body to be subject to any change contrary to the disposition whereby it is perfected by the soul; and consequently those bodies will be impassible.
Reply to Objection 1. According to Anselm (Cur Deus Homo ii, 11), "mortal is included in the philosophers' definition of man, because they did not believe that the whole man could be ever immortal, for they had no experience of man otherwise than in this state of mortality." Or we may say that since, according to the Philosopher (Metaph. vi, 12), essential differences are unknown to us, we sometimes employ accidental differences in order to signify essential differences from which the accidental differences result. Hence "mortal" is put in the definition of man, not as though mortality were essential to man, but because that which causes passibility and mortality in the present state of life, namely composition of contraries, is essential to man, but it will not cause it then, on account of the triumph of the soul over the body.
Reply to Objection 2. Potentiality is twofold, tied and free: and this is true not only of active but also of passive potentiality. For the form ties the potentiality of matter, by determining it to one thing, and it is thus that it overcomes it. And since in corruptible things form does not perfectly overcome matter, it cannot tie it completely so as to prevent it from sometimes receiving a disposition contrary to the form through some passion. But in the saints after the resurrection, the soul will have complete dominion over the body, and it will be altogether impossible for it to lose this dominion, because it will be immutably subject to God, which was not the case in the state of innocence. Consequently those bodies will retain substantially the same potentiality as they have now to another form; yet that potentiality will remain tied by the triumph of the soul over the body, so that it will never be realized by actual passion.
Reply to Objection 3. The elemental qualities are the instruments of the soul, as stated in De Anima ii, text. 38, seqq., for the heat of fire in an animal's body is directed in the act of nutrition by the soul's power. When, however, the principal agent is perfect, and there is no defect in the instrument, no action proceeds from the instrument, except in accordance with the disposition of the principal agent. Consequently in the bodies of the saints after the resurrection, no action or passion will result from the elemental qualities that is contrary to the disposition of the soul which has the preservation of the body in view.
Reply to Objection 4. According to Augustine (Ep. ad Consent. cxlvi) "the Divine power is able to remove" whatever qualities He will "from this visible and tangible body, other qualities remaining." Hence even as in a certain respect "He deprived the flames of the Chaldees' furnace of the power to burn, since the bodies of the children were preserved without hurt, while in another respect that power remained, since those flames consumed the wood, so will He remove passibility from the humors while leaving their nature unchanged." It has been explained in the Article how this is brought about.
Reply to Objection 5. The scars of wounds will not be in the saints, nor were they in Christ, in so far as they imply a defect, but as signs of the most steadfast virtue whereby the saints suffered for the sake of justice and faith: so that this will increase their own and others' joy (Cf. III, 54, 4, ad 3). Hence Augustine says (De Civ. Dei xxii, 19): "We feel an undescribable love for the blessed martyrs so as to desire to see in that kingdom the scars of the wounds in their bodies, which they bore for Christ's name. Perchance indeed we shall see them for this will not make them less comely but more glorious. A certain beauty will shine in them, a beauty though in the body, yet not of the body but of virtue." Nevertheless those martyrs who have been maimed and deprived of their limbs will not be without those limbs in the resurrection of the dead, for to them it is said (Luke 21:18): "A hair of your head shall not perish."
Source: Summa Theologica (New Advent)