27 Here we have the complete explanation of the fact that in your exposition of the faith, to deceive the ears of the ignorant, you nine times make mention of the body, and not even once of the flesh, and all the while men think that you confess the body of flesh, and that the flesh is identical with the body. If it is the same as the body, it means nothing different. I say this, for I know your answer: “I thought the body was the same as the flesh; I spoke with all simplicity.”
Why do you not rather call it flesh to signify the body, and speak indifferently at one time of the flesh, at another of the body, that the body may be shown to consist of flesh, and the flesh to be the body. But believe me, your silence is not the silence of simplicity. For flesh is defined one way, the body another; all flesh is body, but not every body is flesh. Flesh is properly what is comprised in blood, veins, bones, and sinews. Although the body is also called flesh, yet sometimes it is designated ethereal or aërial, because it is not subject to touch and sight; and yet it is frequently both visible and tangible.
A wall is a body, but is not flesh; a stone is a body, but it is not said to be flesh. Wherefore the Apostle calls some bodies celestial, some terrestrial. A celestial body is that of the sun, moon, stars; a terrestrial body is that of fire, air, water, and the rest, which bodies being inanimate are known as consisting of material elements. You see we understand your subtleties, and publish abroad the mysteries which you utter in the bedchamber and among the perfect, mysteries which may not reach the ears of outsiders.
You smile, and with hand uplifted and a snap of the fingers retort, “All the glory of the king's daughter is within.” And, “The king led me into his bedchamber.” It is clear why you spoke of the resurrection of the body and not of that of the flesh; of course it was that we in our ignorance might think that when body was spoken of flesh was meant; while yet the perfect would understand that, when body was spoken of, flesh was denied. Lastly, the Apostle, in his Epistle to the Colossians, wishing to show that the body of Christ was made of flesh, and was not spiritual, aërial, attenuated, said significantly, “And you, when you were some time alienated from Christ and enemies of His spirit in evil works, He has reconciled in the body of His flesh through death.”
And again in the same Epistle: “In whom you were circumcised with a circumcision made without hands in the putting off of the body of the flesh.” If by body is meant flesh only, and the word is not ambiguous, nor capable of diverse significations, it was quite superfluous to use both expressions— bodily and of flesh— as though body did not imply flesh.
Source: To Pammachius Against John of Jerusalem (New Advent)