A sensible man should not demand of me, or hope that when we mention a subject, we shall make a complete exposition of it. - Moshe ben Maimon

[T]he principal part in the human body, namely, the heart, is in constant motion, and is the source of every motion noticed in the body; it rules over the other members, and communicates to them through its own pulsations the force required for their functions. The outermost sphere by its motion rules in a similar way over all other parts of the universe, and supplies all things with their special properties. Every motion in the universe has thus its origin in the motion of that sphere; and the soul of every animated being derives its origin from the soul of that same sphere.

You must know that if a person, who has attained a certain degree of perfection, wishes to impart to others, either orally or in writing, any portion of the knowledge which he has acquired of these subjects, he is utterly unable to be as systematic and explicit as he could be in a science of which the method is well known. The same difficulties which he encountered when investigating the subject for himself will attend him when endeavouring to instruct others: viz., at one time the explanation will appear lucid, at another time, obscure: this property of the subject appears to remain the same both to the advanced scholar and to the beginner. For this reason, great theological scholars gave instruction in all such matters only by means of metaphors and allegories.

It is not unreasonable to assume that the works of God, their existence and preceding non-existence, are the result of His wisdom, but we are unable to understand many of the ways of His Wisdom in His works. On this principle the whole Law of Moses is based; it begins with this principle: "And God saw all that He had made, and behold, it was very good" (Gen. i. 31); and it ends with this principle: "The Rock, perfect is His work" (Deut. xxxii. 4). Note it.