It is doubtful whether this caution proceeded from Cyril himself when issuing a written copy of his Lectures, or from some later editor. Eusebius (E.H. v. 20) has preserved an adjuration by Irenæus at the end of his treatise, On the Ogdoad: I adjure thee, who mayest transcribe this book, by Our Lord Jesus Christ, and by His glorious advent, when He cometh to judge the quick and the dead, to compare what thou hast written and correct it carefully by this copy, from which thou hast transcribed it; this adjuration also thou shalt write in like manner, and set it in the copy.