Tertullian, On the Flesh of Christ 1

People who try to unsettle the faith of the resurrection — which those Sadducean relatives left undisturbed without controversy — so that they may deny that this hope also applies to the flesh, rightly tear Christ's flesh apart with questions, as if it were either nonexistent or somehow other than human; lest, if it is established as human, it be prejudged against them that it rose again in every way, since it rose in Christ. Therefore, from the very source where they destroy the promises of the flesh, we must rebuild them. Let us examine the Lord's bodily substance, for the spiritual substance is certain. The truth of the flesh is sought, and its quality is traced — whether it existed, where it came from, and what kind it was. Its declaration will give the law to our resurrection. Marcion, in order to deny Christ's flesh, also denied the birth; or, to deny the birth, he denied the flesh — clearly so that birth and flesh might not bear mutual witness and answer each other, because neither birth exists without flesh nor flesh without birth. As if the same heretical license were not also available to him: either to deny the birth while admitting the flesh, like his disciple and later deserter Apelles; or to confess both flesh and birth but interpret them differently, like his fellow disciple and fellow deserter Valentinus. But the one who introduced the supposed flesh of Christ could equally have fabricated the birth as a phantom, so that the conception, the pregnant virgin, the birth, and the subsequent order of the infant might have been mere appearances — deceiving the same eyes and senses that the opinion of flesh deceived.