All who believe and are assured that grace and truth were obtained through Jesus Christ, and who know Christ to be the truth, agreeably to His own declaration, “I am the truth,” derive the knowledge which incites men to a good and happy life from no other source than from the very words and teaching of Christ. And by the words of Christ we do not mean those only which He spake when He became man and tabernacled in the flesh; for before that time, Christ, the Word of God, was in Moses and the prophets. For without the Word of God, how could they have been able to prophesy of Christ?

“Preface” to Origen De Principiis [On the Frist Principles] in Ante-Nicene Fathers, 4:239.