Another sect of the Mohammedans which had considerable influence on some of the Jewish philosophical and ethical writers are the ascetics and the Sufis who are related to them. The latter developed their mode of life and their doctrines under the influence of the Christian monks, and are likewise indebted to Indian and Persian ideas.[23] In their mode of life they belong to the class of ascetics and preach abstinence, indifference to human praise and blame, love of God and absolute trust in him even to the extent of refraining from all effort in one's own behalf, and in extreme cases going so far as to court danger. In theoretical teaching they adopted the emanatistic doctrine of the Neo-Platonic School. This has been called dynamic Pantheism. It is Pantheism because in its last analysis it identifies God with the universe. At the same time it does not bring God directly in contact with the world, but only indirectly through the powers or δυνάμεις, hence _dynamic_ Pantheism. These powers emanate successively from the highest one, forming a chain of intermediate powers mediating between God and the world of matter, the links of the chain growing dimmer and less pure as they are further removed from their origin, while the latter loses nothing in the process. This latter condition saves the Neo-Platonic conception from being a pure system of emanation like some Indian doctrines. In the latter the first cause actually gives away something of itself and loses thereby from its fulness. The process in both systems is explained by use of analogies, those of the radiation of light from a luminous body, and of the overflowing of a fountain being the most common. The chief exponent of the ethics of the Sufis in mediæval Jewish literature is Bahya Ibn Pakuda. In his ethical work "The Duties of the Hearts," he lays the same stress on intention and inwardness in religious life and practice as against outward performance with the limbs on the one hand and dry scholasticism on the other, as do the Sufis. In matters of detail too he is very much indebted to this Arab sect from whose writings he quotes abundantly with as well as without acknowledgment of his sources except in a general way as the wise men. To be sure, he does not follow them slavishly and rejects the extremes of asceticism and unworldly cynicism which a great many of the Sufis preached and practiced. He is also not in sympathy with their mysticism. He adopts their teachings only where he can support them with analogous views as expressed in the Rabbinical writings, which indeed played an important rôle in Mohammedan ascetic literature, being the source of many of the sayings found in the latter.[24]