After this, selecting from all the treatises which contain allegorical explanations and interpretations, expressed in a language and style not to be despised, the least important, such as might contribute, indeed, to strengthen the faith of the multitude of simple believers, but were not adapted to impress those of more intelligent mind, he continues: “Of such a nature do I know the work to be, entitled Controversy between one Papiscus and Jason, which is fitted to excite pity and hatred instead of laughter.
It is not my purpose, however, to confute the statements contained in such works; for their fallacy is manifest to all, especially if any one will have the patience to read the books themselves. Rather do I wish to show that Nature teaches this, that God made nothing that is mortal, but that His works, whatever they are, are immortal, and theirs mortal. And the soul is the work of God, while the nature of the body is different. And in this respect there is no difference between the body of a bat, or of a worm, or of a frog, and that of a man; for the matter is the same, and their corruptible part is alike.”
Nevertheless I could wish that every one who heard Celsus declaiming and asserting that the treatise entitled Controversy between Jason and Papiscus regarding Christ was fitted to excite not laughter, but hatred, could take the work into his hands, and patiently listen to its contents; that, finding in it nothing to excite hatred, he might condemn Celsus out of the book itself. For if it be impartially perused, it will be found that there is nothing to excite even laughter in a work in which a Christian is described as conversing with a Jew on the subject of the Jewish Scriptures, and proving that the predictions regarding Christ fitly apply to Jesus; although the other disputant maintains the discussion in no ignoble style, and in a manner not unbecoming the character of a Jew.
Source: Against Celsus (New Advent)