The receptivity of Islam to foreign ideas has been recognised by every unbiassed inquirer, and the history of Sūfism is only a single instance of the general rule. But this fact should not lead us to seek in such ideas an explanation of the whole question which I am now discussing, or to identify Sūfism itself with the extraneous ingredients which it absorbed and assimilated in the course of its development. Even if Islam had been miraculously shut off from contact with foreign religions and philosophies, some form of mysticism would have arisen within it, for the seeds were already there. Of course, we cannot isolate the internal forces working in this direction, since they were subject to the law of spiritual gravitation. The powerful currents of thought discharged through the Mohammedan world by the great non-Islamic systems above mentioned gave a stimulus to various tendencies within Islam which affected Sūfism either positively or negatively. As we have seen, its oldest type is an ascetic revolt against luxury and worldliness; later on, the prevailing rationalism and scepticism provoked counter-movements towards intuitive knowledge and emotional faith, and also an orthodox reaction which in its turn drove many earnest Moslems into the ranks of the mystics. How, it may be asked, could a religion founded on the simple and austere monotheism of Mohammed tolerate these new doctrines, much less make terms with them? It would seem impossible to reconcile the transcendent personality of Allah with an immanent Reality which is the very life and soul of the universe. Yet Islam has accepted Sūfism. The Sūfīs, instead of being excommunicated, are securely established in the Mohammedan church, and the _Legend of the Moslem Saints_ records the wildest excesses of Oriental pantheism. Let us return for a moment to the Koran, that infallible touchstone by which every Mohammedan theory and practice must be proved. Are any germs of mysticism to be found there? The Koran, as I have said, starts with the notion of Allah, the One, Eternal, and Almighty God, far above human feelings and aspirations--the Lord of His slaves, not the Father of His children; a judge meting out stern justice to sinners, and extending His mercy only to those who avert His wrath by repentance, humility, and unceasing works of devotion; a God of fear rather than of love. This is one side, and certainly the most prominent side, of Mohammed’s teaching; but while he set an impassable gulf between the world and Allah, his deeper instinct craved a direct revelation from God to the soul. There are no contradictions in the logic of feeling. Mohammed, who had in him something of the mystic, felt God both as far and near, both as transcendent and immanent. In the latter aspect, Allah is the light of the heavens and the earth, a Being who works in the world and in the soul of man.