Thomas Aquinas

“ Just as the members that serve for generation will be after the resurrection for the integrity of human nature, and not for the operation accomplished now by them, so will the humors be in the body not to make up for waste, but to restore the integrity of human nature and to show forth its natural power. ”

“ Hence whatever humidity of the body belongs to the integrity of human nature must needs rise again in man. Now there is a threefold humidity in man. There is one which occurs as receding from the perfection of the individual---either because it is on the way to corruption, and is voided by nature, for instance urine, sweat, matter, and so forth---or because it is directed by nature to the preservation of the species in some individual, either by the act of the generative power, as seed, or by the act of the nutritive power, as milk. ”

“ And so among the parts of an animated body, some are directed to the accomplishment of the souls' operations, for instance the heart, liver, hand, foot; while others are directed to the safe-keeping of the other parts as leaves to cover fruit; and thus hair and nails are in man for the protection of other parts. Consequently, although they do not belong to the primary perfection of the human body, they belong to the secondary perfection: and since man will rise again with all the perfections of his nature, it follows that hair and nails will rise again in him. ”

“ Wherefore the whole of what is in man will rise again, if we speak of the totality of the species which is dependent on quantity, shape, position and order of parts, but the whole will not rise again if we speak of the totality of matter. ”

“ The third kind of humidity is that which has already reached its ultimate perfection that nature intends in the body of the individual, and has already undergone transformation and become incorporate with the members. ”

“ Just as the elements are in the course of generation in relation to mixed bodies, because they are their matter, yet not so as to be always in transition when in the mixed body, so too are the humors in relation to the members. ”

“ In the other parts something accrues from nourishment which causes growth, and this is reckoned as another part, if we speak of totality of species, since it occupies another place and position in the body, and is under other parts of dimension: and there accrues something which does not cause growth, but serves to make up for waste by nourishing. ”

“ And yet it does not follow that when the operation fails the instrument is useless, because an instrument serves not only to accomplish the operation of the agent, but also to show its virtue. Hence it will be necessary for the virtue of the soul's powers to be shown in their bodily instruments, even though they never proceed to action, so that the wisdom of God be thereby glorified. ”

“ Humidities of this kind will not rise again, because after the resurrection each part of the body will be established in its form, so that one will not pass into another. Wherefore this humidity that is actually in transition from one form to another will not rise again. ”