The truth is, it is sown the barest grain, without a husk to cover it, without a spike even in germ, without the protection of a bearded top, without the glory of a stalk. It rises, however, out of the furrow enriched with a copious crop, built up in a compact fabric, constructed in a beautiful order, fortified by cultivation, and clothed around on every side. These are the circumstances which make it another body from God, to which it is changed not by abolition, but by amplification.
The very same flesh which was once sown in death will bear fruit in resurrection-life —the same in essence, only more full and perfect; not another, although reappearing in another form. For it shall receive in itself the grace and ornament which God shall please to spread over it, according to its merits. … With this view he adds, in a figurative sense, certain examples of animals and heavenly bodies: “There is one flesh of man” (that is, servants of God, but really human), “another flesh of beasts” (that is, the heathen, of whom the prophet actually says, “Man is like the senseless cattle” ), “another flesh of birds” (that is, the martyrs which essay to mount up to heaven), “another of fishes” (that is, those whom the water of baptism has submerged). In like manner does he take examples from the heavenly bodies: “There is one glory of the sun” (that is, of Christ), “and another glory of the moon” (that is, of the Church), “and another glory of the stars” (in other words, of the seed of Abraham). “For one star differeth from another star in glory: so there are bodies terrestrial as well as celestial” (Jews, that is, as well as Christians).
— On the Resurrection of the Flesh LII