First Reason.—The subject itself is difficult, subtle and profound, “Far off and exceeding deep, who can find it out?” (Eccles. vii. 24). The following words of Job may be applied to it: “Whence then cometh wisdom? and where is the place of understanding?” (Job xxviii. 20). Instruction should not begin with abstruse and difficult subjects. In one of the similes contained in the Bible, wisdom is compared to water, and amongst other interpretations given by our Sages of this simile, occurs the following: He who can swim may bring up pearls from the depth of the sea, he who is unable to swim will be drowned, therefore only such persons as have had proper instruction should expose themselves to the risk. Second Reason.—The intelligence of man is at first insufficient; for he is not endowed with perfection at the beginning, but at first possesses perfection only in potentiâ, not in fact. Thus it is said, “And man is born a wild ass” (Job xi. 12). If a man possesses a certain faculty in potentiâ, it does not follow that it must become in him a reality. He may possibly remain deficient either on account of some obstacle, or from want of training in practices which would turn the possibility into a reality. Thus it is distinctly stated in the Bible, “Not many are wise” (ib., xxxii. 9); also our Sages say, “I noticed how few were those who attained to a higher degree of perfection” (B. T. Succah 45a). There are many things which obstruct the path to perfection, and which keep man away from it. Where can he find sufficient preparation and leisure to learn all that is necessary in order to develop that perfection which he has in potentiâ?