Marcion had founded his conception of Christianity on a new canon of Scripture,[70] which seems to have enjoyed the same authority among his followers as was ascribed to the Old Testament in orthodox Christendom. In the Gnostic schools, which likewise rejected the Old Testament altogether or in part, Evangelic and Pauline writings were, by the middle of the second century, treated as sacred texts and made use of to confirm their theological speculations.[71] On the other hand, about the year 150 the main body of Christendom had still no collection of Gospels and Epistles possessing equal authority with the Old Testament, and, apart from Apocalypses, no new writings at all, which as such, that is, as sacred texts, were regarded as inspired and authoritative.[72] Here we leave out of consideration that their content is a testimony of the Spirit. From the works of Justin it is to be inferred that the ultimate authorities were the Old Testament, the words of the Lord, and the communications of Christian prophets.[73] The memoirs of the Apostles ([Greek: apomnemoneumata ton apostolon] = [Greek: ta euangelia]) owed their significance solely to the fact that they recorded the words and history of the Lord and bore witness to the fulfilment of Old Testament predictions. There is no mention whatever of apostolic epistles as holy writings of standard authority.[74] But we learn further from Justin that the Gospels as well as the Old Testament were read in public worship (Apol. I. 67) and that our first three Gospels were already in use. We can, moreover, gather from other sources that other Christian writings, early and late, were more or less regularly read in Christian meetings.[75] Such writings naturally possessed a high degree of authority. As the Holy Spirit and the Church are inseparable, everything that edifies the Church originates with the Holy Spirit,[76] which in this, as well as every other respect, is inexhaustibly rich. Here, however, two interests were predominant from the beginning, that of immediate spiritual edification and that of attesting and certifying the Christian _Kerygma_ ([Greek: he asphaleia ton logon]). _The ecclesiastical canon was the result of the latter interest_, not indeed in consequence of a process of collection, for individual communities had already made a far larger compilation,[77] but, in the first instance, through selection, and afterwards, but not till then, through addition.