John Chrysostom, on 1Cor 15:39

However, he is not content with this, but seeks another difference greater and more manifest. For that thou mayest not, when hearing, as I said, that all rise again, suppose that all enjoy the same reward; he laid before even in the preceding verses the seeds of this thought, saying, "But each in his own order." But he brings it out here also more clearly, saying,

"All flesh is not the same flesh." For why speak I, saith he, in respect of seeds? In respect of bodies let us agitate this point, concerning which we are discoursing now. Wherefore also he addeth, and saith,

"But there is one flesh of men, another flesh of beasts, another of birds, and another of fishes."

"There are also celestial bodies, and bodies terrestrial; but the glory of the celestial is one, and the glory of the terrestrial is another."

"There is one glory of the sun, and another glory of the moon, and another glory of the stars: for one star differeth from another star in glory."

And what means he by these expressions? Wherefore from the resurrection of the body did he throw himself into the discourse of the stars and the sun? He did not throw himself out, neither did he break off from his purpose; far from it: but he still keeps to it. For whereas he had established the doctrine concerning the resurrection, he intimates in what follows that great will be then the difference of glory, though there be but one resurrection. And for the present he divides the whole into two: into "bodies celestial," and "bodies terrestrial." For as the disbelief of the resurrection makes men supine, so again it makes them indolent to think that all are vouchsafed the same reward. Wherefore he corrects both. And the one in the preceeding verses he had completed; but this he begins now. And having made two ranks, of the righteous and of sinners, these same two he subdivides again into many parts, signifying that neither righteous nor sinners shall obtain the same; neither righteous men, all of them, alike with other righteous, nor sinners with other sinners.

Now he makes, you see, first, one separation between righteous and sinners, where he says, "bodies celestial, and bodies terrestrial:" by the "terrestrial" intimating the latter, and by the "celestial," the former. Then farther he introduces a difference of sinners from sinners, saying, "All flesh is not the same flesh, but there is one flesh of fishes, another of birds, and another of beasts." And yet all are bodies; but some are in more, and some in lesser vileness. And that in their manner of living too, and in their very constitution.

And having said this, he ascends again to the heaven, saying, "There is one glory of the sun, and another glory of the moon." For as in the earthly bodies there is a difference, so also in the heavenly; and that difference no ordinary one, but reaching even to the uttermost: there being not only a difference between sun and moon, and stars, but also between stars and stars. For what though they be all in the heaven? yet some have a larger, others a less share of glory. What do we learn from hence? That although they be all in God's kingdom, all shall not enjoy the same reward; and though all sinners be in hell, all shall not endure the same punishment.