But questions arose in regard to all these classes, which were not immediately answered. There were several recensions current both of the sayings of Jesus Christ and of the memoirs of the apostles. There were many writings attributed to apostles and apostolic men which were of doubtful authority. But the determination was slow, and the date when a general settlement was made is uncertain.[690] There is no distinction between canonical and uncanonical books either in Justin Martyr or in Irenæus. The first Biblical critic was Marcion: the controversy with his followers, which reaches its height in Tertullian, forced on the Church the first serious consideration of the question,—Which recensions of the words and memoirs of Christ, and which of the letters and other writings of the apostles and apostolic men, should be accepted? There came to be a recognized list of the writings of the new revelations, as there came to be—though it is doubtful whether there had yet come to be—a list of the writings of the earlier revelations to the Jews. Writings on the recognized list came in as the voices of the Holy Ghost.[691] They were, as the writings of the prophets had been, the revelation of the Father to His children. Hence faith or belief came to take in the Christian world the sense that it had in Philo—of assent not only to the great conceptions which were contained in the notion of God, but also to the divine revelation which was recorded in the two Testaments. * * * * *