Nicene and Post-Nicene Fathers, Ser. II, Vol. III:
Life and Works of Rufinus with Jerome's Apology Against Rufinus.: You try to shield Origen by falsely attributing the Apology for him to Pamphilus.

12. About the book of Pamphilus, what happened to me was, not comical as you call it, but perhaps ridiculous;  3173 namely that after I had asserted it to be by Eusebius not by Pamphilus, I stated at the end of the discussion that I had for many years believed that it was by Pamphilus, and that I p. 525 had borrowed a copy of this book from you. You may judge how little I fear your derision from the fact that even now I make the same statement. I took it from your manuscript as being a copy of a work of Pamphilus. I trusted in you as a Christian and as a monk: I did not imagine that you would be guilty of such a wicked imposture. But, after that the question of Origen’s heresy was stirred throughout the world on account of your translation of his work, I was more careful in examining copies of the book, and in the library of Cæsarea I found the six volumes of Eusebius’ Apology for Origen. As soon as I had looked through them, I at once detected the book on the Son and the Holy Spirit which you alone have published under the name of the martyr, altering most of its blasphemies into words of a better meaning. And this I saw must have been done either by Didymus or by you or some other (it is quite clear that you did it in reference to the Περὶ ᾽Αρχῶν) by this decisive proof, that Eusebius tells us that Pamphilus published nothing of his own. It is for you therefore to say from whence you obtained your copy; and do not, for the sake of avoiding my accusation, say that it was from some one who is dead, or, because you have no one to point to, name one who cannot answer for himself. If this rivulet has its source in your desk, the inference is plain enough, without my drawing it. But, suppose that the title of this book and the name of the author has been changed by some other lover of Origen, what motive had you for turning it into Latin? Evidently this, that, through the testimony given to him by a martyr, all should trust to the writings of Origen, since they were guaranteed beforehand by a witness of such authority. But the Apology of this most learned man was not sufficient for you; you must write a treatise of your own in his defence, and, when these two documents had been widely circulated, you felt secure in proceeding to translate the Περὶ ᾽Αρχῶν itself from the Greek, and commended it in a Preface, in which you said that some things in it had been corrupted by the heretics, but that you had corrected them from a study of others of Origen’s writings. Then come in your praises of me for the purpose of preventing any of my friends from speaking against you. You put me forward as the trumpeter of Origen, you praise my eloquence to the skies, so that you may drag down the faith into the mire; you call me colleague and brother, and profess yourself the imitator of my works. Then, while on the one hand you cry me up as having translated seventy homilies of Origen, and some of his short treatises on the Apostle, in which you say that I so smoothed things down that the Latin reader will find nothing in them which is discrepant from the Catholic faith; now on the other hand you brand these very books as heretical; and, obliterating your former praise, you accuse the man whom you had preached up when you thought he would figure as your ally, because you find that he is the enemy of your perfidy. Which of us two is the calumniator of the martyr? I, who say that he was no heretic, and that he did not write the book which is condemned by every one; or you, who have published a book written by a man who was an Arian and changed his name into that of the martyr? It is not enough for you that Greece has been scandalized; you must press the book upon the ears of the Latins, and dishonor an illustrious martyr as far as in you lies by your translation. Your intention no doubt was not this; it was not to accuse me but to make me serve for the defence of Origen’s writings. But let me tell you that the faith of Rome which was praised by the voice of an Apostle, does not recognize tricks of this kind. A faith which has been guaranteed by the authority of an Apostle cannot be changed though an Angel should announce another gospel than that which he preached. Therefore, my brother, whether the falsification of the book proceeds from you, as many believe, or from another, as you will perhaps try to persuade us, in which case you have only been guilty of rashness in believing the composition of a heretic to be that of a martyr, change the title, and free the innocence of the Romans from this great peril. It is of no advantage to you to be the means of a most illustrious martyr being condemned as a heretic: of one who shed his blood for Christ being proud to be an enemy of the Christian faith. Take another course: say, I found a book which I believed to be the work of a martyr. Do not fear to be a penitent. I will not press you further. I will not ask from whom you obtained it; you can name some dead man if you please, or say you bought it from an unknown man in the street: for I do not wish to see you condemned, but converted. It is better that it should appear that you were in error than that the martyr was a heretic. At all events, by some means or other, draw out your foot from its present entanglement: consider what answer you will make in the judgment to come to the complaints which the martyrs will bring against you.

Footnotes

non ridiculosa ut tu scribis sed ridicula. Jerome seems to object to ridiculosus as bad Latin.