These, briefly, are the fundamental elements in Paul’s doctrine: first, the significance of the death and resurrection of Jesus; second, faith which secures the mystic union with Christ; third, the indwelling Holy Spirit, which completes man’s redemption and moral regeneration. For all Paul doubtless found warrant in the life and words of Jesus, although he seems to have neglected the ethical teachings of the Master. Paul’s views have formed the basis of much of the doctrine of the Church since his time, although his idea of union with Christ through faith soon fell into the background; when it was revived it took on a form very unlike the apostle’s teaching. We have thus far seen two tendencies in Christian thought. The first appears in the synoptic gospels where Jesus is represented as the mediator and teacher, who interpreted to men the universal loving fatherhood of God and showed them their proper relations to God and to their fellow-men; the other is seen in Paul who taught that through the indwelling Christ salvation was secured. It was inevitable that reflective thought should act upon these teachings, and that in the philosophic environment of the Christian churches, at least outside Judea, attempts should be made to apprehend and to formulate in intellectual terms the nature, life, and mission of Jesus—in other words to create a Christian philosophy or theology. When in the period between 50 and 100 A.D., Christianity came into conflict with Hellenistic philosophy and theosophy this work of building up a Christian philosophy began. This stage is the third represented in the New Testament. The so-called Epistle to the Hebrews (c. 90 A.D.) is the first document of the New Testament in which the Greek intellectual habit clearly appears. Although the unknown author was writing to Gentile Christians for practical and not doctrinal ends, there is good evidence that he had been influenced by Alexandrian thought. He presents Christianity as the final and absolute religion, emphasizes Christ’s priestly office and his sacrifice, and gives a more philosophical and abstract definition of faith than any other writer of the New Testament. The great example, however, of the effect of the contact of Christianity with Greek thought is furnished by the Gospel of John and the Johannine Epistles. This fourth Gospel was apparently written at Ephesus, probably between 100 and 110 A.D., by one who was well acquainted with the philosophy and mysticism of his time; he was also strongly influenced by Paul. If the Johannine Epistles are not by the same author, they represent the same range of ideas as the Gospel, and we are therefore justified in using them together with it. The fourth Gospel is much more an interpretation than a history of Jesus’ person and life; it takes for granted that its readers are acquainted with the facts; and it assumes that the church is one universal body.