1. 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,”[3] 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? And were it not our purpose to confine the present treatise within the limits of all attainable brevity, it would not be difficult to show, in proof of this statement, out of the Holy Scriptures, how Moses or the prophets both spake and performed all they did through being filled with the Spirit of Christ. And therefore I think it sufficient to quote this one testimony of Paul from the Epistle to the Hebrews, in which he says: “By faith Moses, when he was come to years, refused to be called the son of Pharaoh’s daughter; choosing rather to suffer affliction with the people of God, than to enjoy the pleasures of sin for a season; esteeming the reproach of Christ greater riches than the treasures of the Egyptians.”[4] Moreover, that after His ascension into heaven He spake in His apostles, is shown by Paul in these words: “Or do you seek a proof of Christ, who speaketh in me?”[5] 2. Since many, however, of those who profess to believe in Christ differ from each other, not only in small and trifling matters, but also on subjects of the highest importance, as _e.g._ regarding God, or the Lord Jesus Christ, or the Holy Spirit; and not only regarding these, but also regarding others which are created existences, viz. the powers[6] and the holy virtues;[7] it seems on that account necessary first of all to fix a definite limit and to lay down an unmistakeable rule regarding each one of these, and then to pass to the investigation of other points. For as we ceased to seek for truth (notwithstanding the professions of many among Greeks and Barbarians to make it known) among all who claimed it for erroneous opinions, after we had come to believe that Christ was the Son of God, and were persuaded that we must learn it from Himself; so, seeing there are many who think they hold the opinions of Christ, and yet some of these think differently from their predecessors, yet as the teaching of the church, transmitted in orderly succession from the apostles, and remaining in the churches to the present day, is still preserved, that alone is to be accepted as truth which differs in no respect from ecclesiastical and apostolical tradition.