Maimonides

He fully knows His unchangeable essence, and has thus a knowledge of all that results from any of His acts. If we were to try to understand in what manner this is done, it would be the same as if we tried to be the same as God, and to make our knowledge identical with His knowledge. Those who seek the truth, and admit what is true, must believe that nothing is hidden from God; that everything is revealed to His knowledge, which is identical with His essence; that this kind of knowledge cannot be comprehended by us; for if we knew its method, we would possess that intellect by which such knowledge could be acquired. ...Note this well, for I think that this is an excellent idea, and leads to correct views; no error will be found in it; no dialectical argument; it does not lead to any absurd conclusion, nor to ascribing any defect to God. These sublime and profound themes admit of no proof whatever... In all questions that cannot be demonstrated, we must adopt the method which we have adopted in this question about God's Omniscience. Note it.

Those who are ignorant and perverse in their thought are constantly in trouble and pain, because they cannot get as much of the superfluous things as a certain other person possesses. They as a rule expose themselves to great dangers... for the purpose of obtaining that which is superfluous and not necessary. When they thus meet with the consequences of the course which they adopt, they complain of the decrees and the judgements of God; they begin to blame the time, and wonder at the want of justice in its changes; that it has not enabled them to acquire great riches... for the purpose of driving themselves to voluptuousness beyond their capacities, as if the whole Universe existed only for the purpose of giving pleasure to these low people.

Transient bodies are only subject to destruction through their substance and not through their form, nor can the essence of their form be destroyed; in this respect they are permanent.

This must be our belief when we have a correct knowledge of our own self, and comprehend the true nature of everything; we must be content, and not trouble our mind with seeking a certain final cause for things that have none, or have no other final cause but their own existence, which depends on the Will of God, or, if you prefer, on the Divine Wisdom.

It is frequently expressed in all parts of Scripture, that the worship of the stars would be followed by absence of rain, devastation of the land, bad times, diseases, and shortness of life. But abandonment of that worship, and the return to the service of God, would be the cause of the presence of rain, fertility of the ground, good times, health and length of life. Thus Scripture teaches, in order that man should abandon idolatry, the reverse of that which idolatrous priests preached to the people, for, as has been shown by us, the principal object of the Law is to remove this doctrine, and to destroy its traces.

The evil into which these philosophers have fallen is greater than that from which they sought to escape, because they refuse to say that God neglects or forgets a thing, and yet they maintain that His knowledge is imperfect, that He is ignorant of what is going on here on earth, that He does not perceive it.

He who thinks he can have flesh and bones without being subject to any external influence, or any accidents of matter, unconsciously wishes to reconcile two opposites, viz., to be at the same time subject and not subject to change. If man were never subject to change there could be no generation; there would be one single being, but no individuals forming a species.

Man's shortcomings and sins are all due to the substance of the body and not to its form; while all his merits are exclusively due to his form.

It was necessary that the very noble form of man, which is the image and likeness of God... should be joined to the substance of dust and darkness, the source of all defect and loss. For these reasons the Creator gave to the form of man power, rule, and dominion over the substance;—the form can subdue the substance, refuse the fulfillment of its desires, and reduce them, as far as possible, to a just and proper measure.

The most evident of the wonders described in the book On the Use of the Limbs [by Galen]... is clearly perceived by all who examine them with a sharp eye. In a similar manner did God provide for each individual animal of the class of mammalia. When such an animal is born it is extremely tender, and cannot be fed with dry food. Therefore breasts were provided which yield milk, and the young can be fed with moist food which corresponds to the condition of the limbs of the animal, until the latter have gradually become dry and hard. Many precepts in our Law are the result of a similar course adopted by the same Supreme Being. It is, namely, impossible to go suddenly from one extreme to the other; it is therefore according to the nature of man impossible for him suddenly to discontinue everything to which he has been accustomed.

Those who believe that... detailed rules originate in a certain cause, are as far from the truth as those who assume that the whole law is useless.

From Moses to Moses there was none like Moses.

The reason of a commandment, whether positive or negative, is clear, and its usefulness evident, if it directly tends to remove injustice, or to teach good conduct that furthers the well-being of society, or to impart a truth which ought to be believed either on its own merit or as being indispensable for facilitating the removal of injustice or the teaching of good morals. There is no occasion to ask for the object of such commandments; for no one can, e.g., be in doubt as to the reason why we have been commanded to believe that God is one; why we are forbidden to murder, steal, and to take vengeance, or to retaliate, or why we are commanded to love one another. But there are precepts concerning which people are in doubt, and of divided opinions, some believing they are mere commands, and serve no purpose whatever, whilst others believe that they serve a certain purpose, which, however is unknown to man. Such are those precepts which in their literal meaning do not seem to further any of the three above-named results: to impart some truth, to teach some moral, or to remove injustice. They do not seem to have any influence upon the well-being of the soul by imparting any truth, or upon the well-being of the body by suggesting such ways and rules as are useful in the government of a state, or in the management of a household. ...I will show that all these and similar laws must have some bearing upon one of the following three things, viz., the regulation of our opinions, or the improvement of our social relations, which implies two things, the removal of injustice, and the teaching of good morals.

The philosophers have uttered very perverse ideas as regards God's Omniscience of everything besides Himself; they have stumbled in such a manner that they cannot rise again, nor can those who adopt their views. ...They continued thus: If he perceives and knows all individual things, one of the following three cases must take place: (1.) God arranges and manages human affairs well, perfectly, and faultlessly; (2.) He is overcome by obstacles, and is too weak and powerless to manage human affairs; (3.) He knows [all things] and can arrange and manage them, but leaves and abandons them, as too base, low, and vile... Those who have a knowledge of a certain thing necessarily either (1.) take care of the thing they know, and manage it, or (2.) neglect it; or (3.) while taking care of it, have not sufficient power and strength for its management, although they have the will to do so. ...the philosophers emphatically decided that of the three cases... two are inadmissible in reference to God—viz., want of power, or absence of will... Consequently there remains only the alternative that God is altogether ignorant of human affairs, or that He knows them and manages them well. ...we conclude that God has no knowledge of them in any way of for any reason. This is the argument which led philosophers to speak such blasphemous words.

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