None of the essential elements in man is altogether annihilated in death. The rational soul, the 'form' of man, remains after death. The matter also remains, which was subject to that form. So by the union of numerically the same soul with numerically the same matter, numerically the same man will be restored.*
What does not bar numerical unity in a man while he lives on uninterruptedly, clearly can be no bar to the identity of the risen man with the man that was. In a man's body while he lives, there are not always the same parts in respect of matter, but only in respect of species. In respect of matter there is a flux and reflux of parts: still that fact does not bar the man's numerical unity from the beginning to the end of his life. We have an example in a fire, which, while it goes on burning, is called numerically one, because its species remains, though the wood is burnt out and fresh wood supplied. So it is in the human body: for the form and species (kind) of the several parts continues unbroken throughout life, but the matter of the parts is dissolved by the natural heat, and new matter accrues by nourishment. But the man is not numerically different by the difference of his component parts at different ages, although it is true that the material composition of the man at one stage of his life is not his material composition at another. So then, for numerically the same man to rise again, it is not requisite for all the material that ever entered into his composition throughout the whole course of his life to be gathered together and resumed, but just so much of it as suffices to make up his proper bulk and stature. We may expect that to be resumed by preference, which was more perfect in the species and form of humanity.* If anything was wanting to his due stature, either through untimely death or mutilation, divine power will supply that from elsewhere. Nor will this supplementary matter mar the personal identity of the risen body: for even in the workmanship of nature addition is made from without to the stature of a boy without prejudice to his identity: for the boy and the adult is numerically the same man.*
The resurrection is natural in respect of its end and term, inasmuch as it is natural to the soul to be united to the body: but its efficient cause is not any agency of nature, but the divine power alone.
All men will rise again, though not all have adhered by faith to Christ, or have received His Sacraments. For the Son of God assumed human nature, in order to restore it: the defect of nature then shall be made good in all, inasmuch as all shall return from death to life: but the defect shall not be perfectly made good except in such as have adhered to Christ, either by their own act believing in Him, or at least by the Sacrament of faith.*
4.79 : That through Christ the Resurrection of our Bodies will take place
4.82 : That Men shall rise again Immortal