Let us stop here for a moment and try to realise what this meant. Mohammed, when founding his new religion, acknowledged, it is true, the books of the former religions, but for his own believers the unique authority is the Koran, a book which originated within a single generation and therefore is pervaded by one uniform spirit. Christianity adhered to a Bible whose larger part originated in a period much anterior to its own and in a religion inferior to Christianity. The Bible covers a period of over a thousand years. What a difference in civilisation between the nomadic life of the patriarchs and the time of Jesus! What a difference in spirit between the sons of Jacob killing the whole population of Sichem in order to avenge their sister and Jesus' parable of the good Samaritan! or between the prophet Elijah killing four hundred and fifty prophets of Baal and Jesus preaching the love of one's enemies! In fact, it was possible to overcome this difference only in an age which did not read the Bible with historical notions. Even so, the juxtaposition caused much difficulty. We shall see the problem of the Law troubling the church through all the centuries. We shall find the notions of sacrifice and priesthood adapted to Christian institutions. Looking at Charlemagne or Calvin, we realise that the Old Testament is ever introducing its views into Christian minds, as authoritative as any word of the gospel. Now, at the beginning the influence was rather the other way; the Old Testament was to be interpreted in the light of the New. And, in truth, much light came from the life of Jesus to the history of the ancient people and to the prophecies. We do not wonder that Christian minds were excited by all this fresh illumination, and we must not wonder that sometimes they remodelled the tradition of the life of Christ to accord with the Old Testament.